Original HTML Proposal for Inline SVG

This is the original proposal for inline SVG in text/html, as found in the most recent draft of HTML5, which was commented out pending feedback from the SVG WG. The SVG WG has proposed modifications to this prose.

Note that sections with the class 'svgSection' (blue background, double blue border) contain the original portions of the proposal that were commented out in the HTML5 draft. Relevant sections are:


8.2 Parsing HTML documents

This section only applies to user agents, data mining tools, and conformance checkers.

The rules for parsing XML documents (and thus XHTML documents) into DOM trees are covered by the next section, entitled "The XHTML syntax".

For HTML documents, user agents must use the parsing rules described in this section to generate the DOM trees. Together, these rules define what is referred to as the HTML parser.

While the HTML form of HTML5 bears a close resemblance to SGML and XML, it is a separate language with its own parsing rules.

Some earlier versions of HTML (in particular from HTML2 to HTML4) were based on SGML and used SGML parsing rules. However, few (if any) web browsers ever implemented true SGML parsing for HTML documents; the only user agents to strictly handle HTML as an SGML application have historically been validators. The resulting confusion — with validators claiming documents to have one representation while widely deployed Web browsers interoperably implemented a different representation — has wasted decades of productivity. This version of HTML thus returns to a non-SGML basis.

Authors interested in using SGML tools in their authoring pipeline are encouraged to use XML tools and the XML serialization of HTML5.

This specification defines the parsing rules for HTML documents, whether they are syntactically correct or not. Certain points in the parsing algorithm are said to be parse errors. The error handling for parse errors is well-defined: user agents must either act as described below when encountering such problems, or must abort processing at the first error that they encounter for which they do not wish to apply the rules described below.

Conformance checkers must report at least one parse error condition to the user if one or more parse error conditions exist in the document and must not report parse error conditions if none exist in the document. Conformance checkers may report more than one parse error condition if more than one parse error conditions exist in the document. Conformance checkers are not required to recover from parse errors.

Parse errors are only errors with the syntax of HTML. In addition to checking for parse errors, conformance checkers will also verify that the document obeys all the other conformance requirements described in this specification.

8.2.1 Overview of the parsing model

The input to the HTML parsing process consists of a stream of Unicode characters, which is passed through a tokenization stage (lexical analysis) followed by a tree construction stage (semantic analysis). The output is a Document object.

Implementations that do not support scripting do not have to actually create a DOM Document object, but the DOM tree in such cases is still used as the model for the rest of the specification.

In the common case, the data handled by the tokenization stage comes from the network, but it can also come from script, e.g. using the document.write() API.

There is only one set of state for the tokeniser stage and the tree construction stage, but the tree construction stage is reentrant, meaning that while the tree construction stage is handling one token, the tokeniser might be resumed, causing further tokens to be emitted and processed before the first token's processing is complete.

In the following example, the tree construction stage will be called upon to handle a "p" start tag token while handling the "script" start tag token:

...
<script>
 document.write('<p>');
</script>
...

To handle these cases, parsers have a script nesting level, which must be initially set to zero, and a parser pause flag, which must be initially set to false.

8.2.2 The input stream

The stream of Unicode characters that consists the input to the tokenization stage will be initially seen by the user agent as a stream of bytes (typically coming over the network or from the local file system). The bytes encode the actual characters according to a particular character encoding, which the user agent must use to decode the bytes into characters.

For XML documents, the algorithm user agents must use to determine the character encoding is given by the XML specification. This section does not apply to XML documents. [XML]

8.2.2.1 Determining the character encoding

In some cases, it might be impractical to unambiguously determine the encoding before parsing the document. Because of this, this specification provides for a two-pass mechanism with an optional pre-scan. Implementations are allowed, as described below, to apply a simplified parsing algorithm to whatever bytes they have available before beginning to parse the document. Then, the real parser is started, using a tentative encoding derived from this pre-parse and other out-of-band metadata. If, while the document is being loaded, the user agent discovers an encoding declaration that conflicts with this information, then the parser can get reinvoked to perform a parse of the document with the real encoding.

User agents must use the following algorithm (the encoding sniffing algorithm) to determine the character encoding to use when decoding a document in the first pass. This algorithm takes as input any out-of-band metadata available to the user agent (e.g. the Content-Type metadata of the document) and all the bytes available so far, and returns an encoding and a confidence. The confidence is either tentative, certain, or irrelevant. The encoding used, and whether the confidence in that encoding is tentative or confident, is used during the parsing to determine whether to change the encoding. If no encoding is necessary, e.g. because the parser is operating on a stream of Unicode characters and doesn't have to use an encoding at all, then the confidence is irrelevant.

  1. If the transport layer specifies an encoding, and it is supported, return that encoding with the confidence certain, and abort these steps.

  2. The user agent may wait for more bytes of the resource to be available, either in this step or at any later step in this algorithm. For instance, a user agent might wait 500ms or 512 bytes, whichever came first. In general preparsing the source to find the encoding improves performance, as it reduces the need to throw away the data structures used when parsing upon finding the encoding information. However, if the user agent delays too long to obtain data to determine the encoding, then the cost of the delay could outweigh any performance improvements from the preparse.

  3. For each of the rows in the following table, starting with the first one and going down, if there are as many or more bytes available than the number of bytes in the first column, and the first bytes of the file match the bytes given in the first column, then return the encoding given in the cell in the second column of that row, with the confidence certain, and abort these steps:

    Bytes in Hexadecimal Encoding
    FE FF UTF-16BE
    FF FE UTF-16LE
    EF BB BF UTF-8

    This step looks for Unicode Byte Order Marks (BOMs).

  4. Otherwise, the user agent will have to search for explicit character encoding information in the file itself. This should proceed as follows:

    Let position be a pointer to a byte in the input stream, initially pointing at the first byte. If at any point during these substeps the user agent either runs out of bytes or decides that scanning further bytes would not be efficient, then skip to the next step of the overall character encoding detection algorithm. User agents may decide that scanning any bytes is not efficient, in which case these substeps are entirely skipped.

    Now, repeat the following "two" steps until the algorithm aborts (either because user agent aborts, as described above, or because a character encoding is found):

    1. If position points to:

      A sequence of bytes starting with: 0x3C 0x21 0x2D 0x2D (ASCII '<!--')

      Advance the position pointer so that it points at the first 0x3E byte which is preceded by two 0x2D bytes (i.e. at the end of an ASCII '-->' sequence) and comes after the 0x3C byte that was found. (The two 0x2D bytes can be the same as the those in the '<!--' sequence.)

      A sequence of bytes starting with: 0x3C, 0x4D or 0x6D, 0x45 or 0x65, 0x54 or 0x74, 0x41 or 0x61, and finally one of 0x09, 0x0A, 0x0C, 0x0D, 0x20, 0x2F (case-insensitive ASCII '<meta' followed by a space or slash)
      1. Advance the position pointer so that it points at the next 0x09, 0x0A, 0x0C, 0x0D, 0x20, or 0x2F byte (the one in sequence of characters matched above).

      2. Get an attribute and its value. If no attribute was sniffed, then skip this inner set of steps, and jump to the second step in the overall "two step" algorithm.

      3. If the attribute's name is neither "charset" nor "content", then return to step 2 in these inner steps.

      4. If the attribute's name is "charset", let charset be the attribute's value, interpreted as a character encoding.

      5. Otherwise, the attribute's name is "content": apply the algorithm for extracting an encoding from a Content-Type, giving the attribute's value as the string to parse. If an encoding is returned, let charset be that encoding. Otherwise, return to step 2 in these inner steps.

      6. If charset is a UTF-16 encoding, change it to UTF-8.

      7. If charset is a supported character encoding, then return the given encoding, with confidence tentative, and abort all these steps.

      8. Otherwise, return to step 2 in these inner steps.

      A sequence of bytes starting with a 0x3C byte (ASCII '<'), optionally a 0x2F byte (ASCII '/'), and finally a byte in the range 0x41-0x5A or 0x61-0x7A (an ASCII letter)
      1. Advance the position pointer so that it points at the next 0x09 (ASCII TAB), 0x0A (ASCII LF), 0x0C (ASCII FF), 0x0D (ASCII CR), 0x20 (ASCII space), or 0x3E (ASCII '>') byte.

      2. Repeatedly get an attribute until no further attributes can be found, then jump to the second step in the overall "two step" algorithm.

      A sequence of bytes starting with: 0x3C 0x21 (ASCII '<!')
      A sequence of bytes starting with: 0x3C 0x2F (ASCII '</')
      A sequence of bytes starting with: 0x3C 0x3F (ASCII '<?')

      Advance the position pointer so that it points at the first 0x3E byte (ASCII '>') that comes after the 0x3C byte that was found.

      Any other byte

      Do nothing with that byte.

    2. Move position so it points at the next byte in the input stream, and return to the first step of this "two step" algorithm.

    When the above "two step" algorithm says to get an attribute, it means doing this:

    1. If the byte at position is one of 0x09 (ASCII TAB), 0x0A (ASCII LF), 0x0C (ASCII FF), 0x0D (ASCII CR), 0x20 (ASCII space), or 0x2F (ASCII '/') then advance position to the next byte and redo this substep.

    2. If the byte at position is 0x3E (ASCII '>'), then abort the "get an attribute" algorithm. There isn't one.

    3. Otherwise, the byte at position is the start of the attribute name. Let attribute name and attribute value be the empty string.

    4. Attribute name: Process the byte at position as follows:

      If it is 0x3D (ASCII '='), and the attribute name is longer than the empty string
      Advance position to the next byte and jump to the step below labeled value.
      If it is 0x09 (ASCII TAB), 0x0A (ASCII LF), 0x0C (ASCII FF), 0x0D (ASCII CR), or 0x20 (ASCII space)
      Jump to the step below labeled spaces.
      If it is 0x2F (ASCII '/') or 0x3E (ASCII '>')
      Abort the "get an attribute" algorithm. The attribute's name is the value of attribute name, its value is the empty string.
      If it is in the range 0x41 (ASCII 'A') to 0x5A (ASCII 'Z')
      Append the Unicode character with codepoint b+0x20 to attribute name (where b is the value of the byte at position).
      Anything else
      Append the Unicode character with the same codepoint as the value of the byte at position) to attribute name. (It doesn't actually matter how bytes outside the ASCII range are handled here, since only ASCII characters can contribute to the detection of a character encoding.)
    5. Advance position to the next byte and return to the previous step.

    6. Spaces. If the byte at position is one of 0x09 (ASCII TAB), 0x0A (ASCII LF), 0x0C (ASCII FF), 0x0D (ASCII CR), or 0x20 (ASCII space) then advance position to the next byte, then, repeat this step.

    7. If the byte at position is not 0x3D (ASCII '='), abort the "get an attribute" algorithm. The attribute's name is the value of attribute name, its value is the empty string.

    8. Advance position past the 0x3D (ASCII '=') byte.

    9. Value. If the byte at position is one of 0x09 (ASCII TAB), 0x0A (ASCII LF), 0x0C (ASCII FF), 0x0D (ASCII CR), or 0x20 (ASCII space) then advance position to the next byte, then, repeat this step.

    10. Process the byte at position as follows:

      If it is 0x22 (ASCII '"') or 0x27 ("'")
      1. Let b be the value of the byte at position.
      2. Advance position to the next byte.
      3. If the value of the byte at position is the value of b, then advance position to the next byte and abort the "get an attribute" algorithm. The attribute's name is the value of attribute name, and its value is the value of attribute value.
      4. Otherwise, if the value of the byte at position is in the range 0x41 (ASCII 'A') to 0x5A (ASCII 'Z'), then append a Unicode character to attribute value whose codepoint is 0x20 more than the value of the byte at position.
      5. Otherwise, append a Unicode character to attribute value whose codepoint is the same as the value of the byte at position.
      6. Return to the second step in these substeps.
      If it is 0x3E (ASCII '>')
      Abort the "get an attribute" algorithm. The attribute's name is the value of attribute name, its value is the empty string.
      If it is in the range 0x41 (ASCII 'A') to 0x5A (ASCII 'Z')
      Append the Unicode character with codepoint b+0x20 to attribute value (where b is the value of the byte at position). Advance position to the next byte.
      Anything else
      Append the Unicode character with the same codepoint as the value of the byte at position) to attribute value. Advance position to the next byte.
    11. Process the byte at position as follows:

      If it is 0x09 (ASCII TAB), 0x0A (ASCII LF), 0x0C (ASCII FF), 0x0D (ASCII CR), 0x20 (ASCII space), or 0x3E (ASCII '>')
      Abort the "get an attribute" algorithm. The attribute's name is the value of attribute name and its value is the value of attribute value.
      If it is in the range 0x41 (ASCII 'A') to 0x5A (ASCII 'Z')
      Append the Unicode character with codepoint b+0x20 to attribute value (where b is the value of the byte at position).
      Anything else
      Append the Unicode character with the same codepoint as the value of the byte at position) to attribute value.
    12. Advance position to the next byte and return to the previous step.

    For the sake of interoperability, user agents should not use a pre-scan algorithm that returns different results than the one described above. (But, if you do, please at least let us know, so that we can improve this algorithm and benefit everyone...)

  5. If the user agent has information on the likely encoding for this page, e.g. based on the encoding of the page when it was last visited, then return that encoding, with the confidence tentative, and abort these steps.

  6. The user agent may attempt to autodetect the character encoding from applying frequency analysis or other algorithms to the data stream. If autodetection succeeds in determining a character encoding, then return that encoding, with the confidence tentative, and abort these steps. [UNIVCHARDET]

  7. Otherwise, return an implementation-defined or user-specified default character encoding, with the confidence tentative. In non-legacy environments, the more comprehensive UTF-8 encoding is recommended. Due to its use in legacy content, windows-1252 is recommended as a default in predominantly Western demographics instead. Since these encodings can in many cases be distinguished by inspection, a user agent may heuristically decide which to use as a default.

The document's character encoding must immediately be set to the value returned from this algorithm, at the same time as the user agent uses the returned value to select the decoder to use for the input stream.

8.2.2.2 Preprocessing the input stream

Given an encoding, the bytes in the input stream must be converted to Unicode characters for the tokeniser, as described by the rules for that encoding, except that the leading U+FEFF BYTE ORDER MARK character, if any, must not be stripped by the encoding layer (it is stripped by the rule below).

Bytes or sequences of bytes in the original byte stream that could not be converted to Unicode characters must be converted to U+FFFD REPLACEMENT CHARACTER code points.

Bytes or sequences of bytes in the original byte stream that did not conform to the encoding specification (e.g. invalid UTF-8 byte sequences in a UTF-8 input stream) are errors that conformance checkers are expected to report.

Any byte or sequences of bytes in the original byte stream that is misinterpreted for compatibility is a parse error.

One leading U+FEFF BYTE ORDER MARK character must be ignored if any are present.

All U+0000 NULL characters in the input must be replaced by U+FFFD REPLACEMENT CHARACTERs. Any occurrences of such characters is a parse error.

Any occurrences of any characters in the ranges U+0001 to U+0008, U+000E to U+001F, U+007F to U+009F, U+D800 to U+DFFF, U+FDD0 to U+FDEF, and characters U+000B, U+FFFE, U+FFFF, U+1FFFE, U+1FFFF, U+2FFFE, U+2FFFF, U+3FFFE, U+3FFFF, U+4FFFE, U+4FFFF, U+5FFFE, U+5FFFF, U+6FFFE, U+6FFFF, U+7FFFE, U+7FFFF, U+8FFFE, U+8FFFF, U+9FFFE, U+9FFFF, U+AFFFE, U+AFFFF, U+BFFFE, U+BFFFF, U+CFFFE, U+CFFFF, U+DFFFE, U+DFFFF, U+EFFFE, U+EFFFF, U+FFFFE, U+FFFFF, U+10FFFE, and U+10FFFF are parse errors. (These are all control characters or permanently undefined Unicode characters.)

U+000D CARRIAGE RETURN (CR) characters and U+000A LINE FEED (LF) characters are treated specially. Any CR characters that are followed by LF characters must be removed, and any CR characters not followed by LF characters must be converted to LF characters. Thus, newlines in HTML DOMs are represented by LF characters, and there are never any CR characters in the input to the tokenization stage.

The next input character is the first character in the input stream that has not yet been consumed. Initially, the next input character is the first character in the input. The current input character is the last character to have been consumed.

The insertion point is the position (just before a character or just before the end of the input stream) where content inserted using document.write() is actually inserted. The insertion point is relative to the position of the character immediately after it, it is not an absolute offset into the input stream. Initially, the insertion point is uninitialized.

The "EOF" character in the tables below is a conceptual character representing the end of the input stream. If the parser is a script-created parser, then the end of the input stream is reached when an explicit "EOF" character (inserted by the document.close() method) is consumed. Otherwise, the "EOF" character is not a real character in the stream, but rather the lack of any further characters.

8.2.2.3 Changing the encoding while parsing

When the parser requires the user agent to change the encoding, it must run the following steps. This might happen if the encoding sniffing algorithm described above failed to find an encoding, or if it found an encoding that was not the actual encoding of the file.

  1. If the new encoding is a UTF-16 encoding, change it to UTF-8.
  2. If the new encoding is identical or equivalent to the encoding that is already being used to interpret the input stream, then set the confidence to confident and abort these steps. This happens when the encoding information found in the file matches what the encoding sniffing algorithm determined to be the encoding, and in the second pass through the parser if the first pass found that the encoding sniffing algorithm described in the earlier section failed to find the right encoding.
  3. If all the bytes up to the last byte converted by the current decoder have the same Unicode interpretations in both the current encoding and the new encoding, and if the user agent supports changing the converter on the fly, then the user agent may change to the new converter for the encoding on the fly. Set the document's character encoding and the encoding used to convert the input stream to the new encoding, set the confidence to confident, and abort these steps.
  4. Otherwise, navigate to the document again, with replacement enabled, and using the same source browsing context, but this time skip the encoding sniffing algorithm and instead just set the encoding to the new encoding and the confidence to confident. Whenever possible, this should be done without actually contacting the network layer (the bytes should be re-parsed from memory), even if, e.g., the document is marked as not being cacheable. If this is not possible and contacting the network layer would involve repeating a request that uses a method other than HTTP GET (or equivalent for non-HTTP URLs), then instead set the confidence to confident and ignore the new encoding. The resource will be misinterpreted. User agents may notify the user of the situation, to aid in application development.

8.2.3 Parse state

8.2.3.1 The insertion mode

The insertion mode is a flag that controls the primary operation of the tree construction stage.

Initially the insertion mode is "initial". It can change to "before html", "before head", "in head", "in head noscript", "after head", "in body", "in CDATA/RCDATA", "in table", "in caption", "in column group", "in table body", "in row", "in cell", "in select", "in select in table", "in foreign content", "after body", "in frameset", "after frameset", "after after body", and "after after frameset" during the course of the parsing, as described in the tree construction stage. The insertion mode affects how tokens are processed and whether CDATA sections are supported.

Seven of these modes, namely "in head", "in body", "in CDATA/RCDATA", "in table", "in table body", "in row", "in cell", and "in select", are special, in that the other modes defer to them at various times. When the algorithm below says that the user agent is to do something "using the rules for the m insertion mode", where m is one of these modes, the user agent must use the rules described under the m insertion mode's section, but must leave the insertion mode unchanged unless the rules in m themselves switch the insertion mode to a new value.

When the insertion mode is switched to "in CDATA/RCDATA", the original insertion mode is also set. This is the insertion mode to which the tree construction stage will return when the corresponding end tag is parsed.

When the insertion mode is switched to "in foreign content", the secondary insertion mode is also set. This secondary mode is used within the rules for the "in foreign content" mode to handle HTML (i.e. not foreign) content.


When the steps below require the UA to reset the insertion mode appropriately, it means the UA must follow these steps:

  1. Let last be false.
  2. Let node be the last node in the stack of open elements.
  3. If node is the first node in the stack of open elements, then set last to true and set node to the context element. (fragment case)
  4. If node is a select element, then switch the insertion mode to "in select" and abort these steps. (fragment case)
  5. If node is a td or th element and last is false, then switch the insertion mode to "in cell" and abort these steps.
  6. If node is a tr element, then switch the insertion mode to "in row" and abort these steps.
  7. If node is a tbody, thead, or tfoot element, then switch the insertion mode to "in table body" and abort these steps.
  8. If node is a caption element, then switch the insertion mode to "in caption" and abort these steps.
  9. If node is a colgroup element, then switch the insertion mode to "in column group" and abort these steps. (fragment case)
  10. If node is a table element, then switch the insertion mode to "in table" and abort these steps.
  11. If node is an element from the MathML namespace, then switch the insertion mode to "in foreign content", let the secondary insertion mode be "in body", and abort these steps.
  12. If node is a head element, then switch the insertion mode to "in body" ("in body"! not "in head"!) and abort these steps. (fragment case)
  13. If node is a body element, then switch the insertion mode to "in body" and abort these steps.
  14. If node is a frameset element, then switch the insertion mode to "in frameset" and abort these steps. (fragment case)
  15. If node is an html element, then: if the head element pointer is null, switch the insertion mode to "before head", otherwise, switch the insertion mode to "after head". In either case, abort these steps. (fragment case)
  16. If last is true, then switch the insertion mode to "in body" and abort these steps. (fragment case)
  17. Let node now be the node before node in the stack of open elements.
  18. Return to step 3.
8.2.3.2 The stack of open elements

Initially the stack of open elements is empty. The stack grows downwards; the topmost node on the stack is the first one added to the stack, and the bottommost node of the stack is the most recently added node in the stack (notwithstanding when the stack is manipulated in a random access fashion as part of the handling for misnested tags).

The "before html" insertion mode creates the html root element node, which is then added to the stack.

In the fragment case, the stack of open elements is initialized to contain an html element that is created as part of that algorithm. (The fragment case skips the "before html" insertion mode.)

The html node, however it is created, is the topmost node of the stack. It never gets popped off the stack.

The current node is the bottommost node in this stack.

The current table is the last table element in the stack of open elements, if there is one. If there is no table element in the stack of open elements (fragment case), then the current table is the first element in the stack of open elements (the html element).

Elements in the stack fall into the following categories:

Special

The following HTML elements have varying levels of special parsing rules: address, area, article, aside, base, basefont, bgsound, blockquote, body, br, center, col, colgroup, command, datagrid, dd, details, dialog, dir, div, dl, dt, embed, fieldset, figure, footer, form, frame, frameset, h1, h2, h3, h4, h5, h6, head, header, hr, iframe, img, input, isindex, li, link, listing, menu, meta, nav, noembed, noframes, noscript, ol, p, param, plaintext, pre, script, section, select, spacer, style, tbody, textarea, tfoot, thead, title, tr, ul, and wbr.

Scoping

The following HTML elements introduce new scopes for various parts of the parsing: applet, button, caption, html, marquee, object, table, td, th.

Formatting

The following HTML elements are those that end up in the list of active formatting elements: a, b, big, code, em, font, i, nobr, s, small, strike, strong, tt, and u.

Phrasing

All other elements found while parsing an HTML document.

The stack of open elements is said to have an element in scope when the following algorithm terminates in a match state:

  1. Initialize node to be the current node (the bottommost node of the stack).

  2. If node is the target node, terminate in a match state.

  3. Otherwise, if node is one of the following elements, terminate in a failure state:

  4. Otherwise, set node to the previous entry in the stack of open elements and return to step 2. (This will never fail, since the loop will always terminate in the previous step if the top of the stack — an html element — is reached.)

The stack of open elements is said to have an element in table scope when the following algorithm terminates in a match state:

  1. Initialize node to be the current node (the bottommost node of the stack).

  2. If node is the target node, terminate in a match state.

  3. Otherwise, if node is one of the following elements, terminate in a failure state:

  4. Otherwise, set node to the previous entry in the stack of open elements and return to step 2. (This will never fail, since the loop will always terminate in the previous step if the top of the stack — an html element — is reached.)

Nothing happens if at any time any of the elements in the stack of open elements are moved to a new location in, or removed from, the Document tree. In particular, the stack is not changed in this situation. This can cause, amongst other strange effects, content to be appended to nodes that are no longer in the DOM.

In some cases (namely, when closing misnested formatting elements), the stack is manipulated in a random-access fashion.

8.2.3.3 The list of active formatting elements

Initially the list of active formatting elements is empty. It is used to handle mis-nested formatting element tags.

The list contains elements in the formatting category, and scope markers. The scope markers are inserted when entering applet elements, buttons, object elements, marquees, table cells, and table captions, and are used to prevent formatting from "leaking" into applet elements, buttons, object elements, marquees, and tables.

When the steps below require the UA to reconstruct the active formatting elements, the UA must perform the following steps:

  1. If there are no entries in the list of active formatting elements, then there is nothing to reconstruct; stop this algorithm.
  2. If the last (most recently added) entry in the list of active formatting elements is a marker, or if it is an element that is in the stack of open elements, then there is nothing to reconstruct; stop this algorithm.
  3. Let entry be the last (most recently added) element in the list of active formatting elements.
  4. If there are no entries before entry in the list of active formatting elements, then jump to step 8.
  5. Let entry be the entry one earlier than entry in the list of active formatting elements.
  6. If entry is neither a marker nor an element that is also in the stack of open elements, go to step 4.
  7. Let entry be the element one later than entry in the list of active formatting elements.
  8. Perform a shallow clone of the element entry to obtain clone. [DOM3CORE]
  9. Append clone to the current node and push it onto the stack of open elements so that it is the new current node.
  10. Replace the entry for entry in the list with an entry for clone.
  11. If the entry for clone in the list of active formatting elements is not the last entry in the list, return to step 7.

This has the effect of reopening all the formatting elements that were opened in the current body, cell, or caption (whichever is youngest) that haven't been explicitly closed.

The way this specification is written, the list of active formatting elements always consists of elements in chronological order with the least recently added element first and the most recently added element last (except for while steps 8 to 11 of the above algorithm are being executed, of course).

When the steps below require the UA to clear the list of active formatting elements up to the last marker, the UA must perform the following steps:

  1. Let entry be the last (most recently added) entry in the list of active formatting elements.
  2. Remove entry from the list of active formatting elements.
  3. If entry was a marker, then stop the algorithm at this point. The list has been cleared up to the last marker.
  4. Go to step 1.
8.2.3.4 The element pointers

Initially the head element pointer and the form element pointer are both null.

Once a head element has been parsed (whether implicitly or explicitly) the head element pointer gets set to point to this node.

The form element pointer points to the last form element that was opened and whose end tag has not yet been seen. It is used to make form controls associate with forms in the face of dramatically bad markup, for historical reasons.

8.2.3.5 Other parsing state flags

The scripting flag is set to "enabled" if scripting was enabled for the Document with which the parser is associated when the parser was created, and "disabled" otherwise.

The frameset-ok flag is set to "ok" when the parser is created. It is set to "not ok" after certain tokens are seen.

8.2.4 Tokenization

Implementations must act as if they used the following state machine to tokenise HTML. The state machine must start in the data state. Most states consume a single character, which may have various side-effects, and either switches the state machine to a new state to reconsume the same character, or switches it to a new state (to consume the next character), or repeats the same state (to consume the next character). Some states have more complicated behavior and can consume several characters before switching to another state.

The exact behavior of certain states depends on a content model flag that is set after certain tokens are emitted. The flag has several states: PCDATA, RCDATA, CDATA, and PLAINTEXT. Initially it must be in the PCDATA state. In the RCDATA and CDATA states, a further escape flag is used to control the behavior of the tokeniser. It is either true or false, and initially must be set to the false state. The insertion mode and the stack of open elements also affects tokenization.

The output of the tokenization step is a series of zero or more of the following tokens: DOCTYPE, start tag, end tag, comment, character, end-of-file. DOCTYPE tokens have a name, a public identifier, a system identifier, and a force-quirks flag. When a DOCTYPE token is created, its name, public identifier, and system identifier must be marked as missing (which is a distinct state from the empty string), and the force-quirks flag must be set to off (its other state is on). Start and end tag tokens have a tag name, a self-closing flag, and a list of attributes, each of which has a name and a value. When a start or end tag token is created, its self-closing flag must be unset (its other state is that it be set), and its attributes list must be empty. Comment and character tokens have data.

When a token is emitted, it must immediately be handled by the tree construction stage. The tree construction stage can affect the state of the content model flag, and can insert additional characters into the stream. (For example, the script element can result in scripts executing and using the dynamic markup insertion APIs to insert characters into the stream being tokenised.)

When a start tag token is emitted with its self-closing flag set, if the flag is not acknowledged when it is processed by the tree construction stage, that is a parse error.

When an end tag token is emitted, the content model flag must be switched to the PCDATA state.

When an end tag token is emitted with attributes, that is a parse error.

When an end tag token is emitted with its self-closing flag set, that is a parse error.

Before each step of the tokeniser, the user agent must first check the parser pause flag. If it is true, then the tokeniser must abort the processing of any nested invocations of the tokeniser, yielding control back to the caller. If it is false, then the user agent may then check to see if either one of the scripts in the list of scripts that will execute as soon as possible or the first script in the list of scripts that will execute asynchronously, has completed loading. If one has, then it must be executed and removed from its list.

The tokeniser state machine consists of the states defined in the following subsections.

8.2.4.1 Data state

Consume the next input character:

U+0026 AMPERSAND (&)
When the content model flag is set to one of the PCDATA or RCDATA states and the escape flag is false: switch to the character reference data state.
Otherwise: treat it as per the "anything else" entry below.
U+002D HYPHEN-MINUS (-)

If the content model flag is set to either the RCDATA state or the CDATA state, and the escape flag is false, and there are at least three characters before this one in the input stream, and the last four characters in the input stream, including this one, are U+003C LESS-THAN SIGN, U+0021 EXCLAMATION MARK, U+002D HYPHEN-MINUS, and U+002D HYPHEN-MINUS ("<!--"), then set the escape flag to true.

In any case, emit the input character as a character token. Stay in the data state.

U+003C LESS-THAN SIGN (<)
When the content model flag is set to the PCDATA state: switch to the tag open state.
When the content model flag is set to either the RCDATA state or the CDATA state, and the escape flag is false: switch to the tag open state.
Otherwise: treat it as per the "anything else" entry below.
U+003E GREATER-THAN SIGN (>)

If the content model flag is set to either the RCDATA state or the CDATA state, and the escape flag is true, and the last three characters in the input stream including this one are U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS, U+003E GREATER-THAN SIGN ("-->"), set the escape flag to false.

In any case, emit the input character as a character token. Stay in the data state.

EOF
Emit an end-of-file token.
Anything else
Emit the input character as a character token. Stay in the data state.
8.2.4.2 Character reference data state

(This cannot happen if the content model flag is set to the CDATA state.)

Attempt to consume a character reference, with no additional allowed character.

If nothing is returned, emit a U+0026 AMPERSAND character token.

Otherwise, emit the character token that was returned.

Finally, switch to the data state.

8.2.4.3 Tag open state

The behavior of this state depends on the content model flag.

If the content model flag is set to the RCDATA or CDATA states

Consume the next input character. If it is a U+002F SOLIDUS (/) character, switch to the close tag open state. Otherwise, emit a U+003C LESS-THAN SIGN character token and reconsume the current input character in the data state.

If the content model flag is set to the PCDATA state

Consume the next input character:

U+0021 EXCLAMATION MARK (!)
Switch to the markup declaration open state.
U+002F SOLIDUS (/)
Switch to the close tag open state.
U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Create a new start tag token, set its tag name to the lowercase version of the input character (add 0x0020 to the character's code point), then switch to the tag name state. (Don't emit the token yet; further details will be filled in before it is emitted.)
U+0061 LATIN SMALL LETTER A through to U+007A LATIN SMALL LETTER Z
Create a new start tag token, set its tag name to the input character, then switch to the tag name state. (Don't emit the token yet; further details will be filled in before it is emitted.)
U+003E GREATER-THAN SIGN (>)
Parse error. Emit a U+003C LESS-THAN SIGN character token and a U+003E GREATER-THAN SIGN character token. Switch to the data state.
U+003F QUESTION MARK (?)
Parse error. Switch to the bogus comment state.
Anything else
Parse error. Emit a U+003C LESS-THAN SIGN character token and reconsume the current input character in the data state.
8.2.4.4 Close tag open state

If the content model flag is set to the RCDATA or CDATA states but no start tag token has ever been emitted by this instance of the tokeniser (fragment case), or, if the content model flag is set to the RCDATA or CDATA states and the next few characters do not match the tag name of the last start tag token emitted (compared in an ASCII case-insensitive manner), or if they do but they are not immediately followed by one of the following characters:

...then emit a U+003C LESS-THAN SIGN character token, a U+002F SOLIDUS character token, and switch to the data state to process the next input character.

Otherwise, if the content model flag is set to the PCDATA state, or if the next few characters do match that tag name, consume the next input character:

U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Create a new end tag token, set its tag name to the lowercase version of the input character (add 0x0020 to the character's code point), then switch to the tag name state. (Don't emit the token yet; further details will be filled in before it is emitted.)
U+0061 LATIN SMALL LETTER A through to U+007A LATIN SMALL LETTER Z
Create a new end tag token, set its tag name to the input character, then switch to the tag name state. (Don't emit the token yet; further details will be filled in before it is emitted.)
U+003E GREATER-THAN SIGN (>)
Parse error. Switch to the data state.
EOF
Parse error. Emit a U+003C LESS-THAN SIGN character token and a U+002F SOLIDUS character token. Reconsume the EOF character in the data state.
Anything else
Parse error. Switch to the bogus comment state.
8.2.4.5 Tag name state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Switch to the before attribute name state.
U+002F SOLIDUS (/)
Switch to the self-closing start tag state.
U+003E GREATER-THAN SIGN (>)
Emit the current tag token. Switch to the data state.
U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Append the lowercase version of the current input character (add 0x0020 to the character's code point) to the current tag token's tag name. Stay in the tag name state.
EOF
Parse error. Emit the current tag token. Reconsume the EOF character in the data state.
Anything else
Append the current input character to the current tag token's tag name. Stay in the tag name state.
8.2.4.6 Before attribute name state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the before attribute name state.
U+002F SOLIDUS (/)
Switch to the self-closing start tag state.
U+003E GREATER-THAN SIGN (>)
Emit the current tag token. Switch to the data state.
U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Start a new attribute in the current tag token. Set that attribute's name to the lowercase version of the current input character (add 0x0020 to the character's code point), and its value to the empty string. Switch to the attribute name state.
U+0022 QUOTATION MARK (")
U+0027 APOSTROPHE (')
U+003D EQUALS SIGN (=)
Parse error. Treat it as per the "anything else" entry below.
EOF
Parse error. Emit the current tag token. Reconsume the EOF character in the data state.
Anything else
Start a new attribute in the current tag token. Set that attribute's name to the current input character, and its value to the empty string. Switch to the attribute name state.
8.2.4.7 Attribute name state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Switch to the after attribute name state.
U+002F SOLIDUS (/)
Switch to the self-closing start tag state.
U+003D EQUALS SIGN (=)
Switch to the before attribute value state.
U+003E GREATER-THAN SIGN (>)
Emit the current tag token. Switch to the data state.
U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Append the lowercase version of the current input character (add 0x0020 to the character's code point) to the current attribute's name. Stay in the attribute name state.
U+0022 QUOTATION MARK (")
U+0027 APOSTROPHE (')
Parse error. Treat it as per the "anything else" entry below.
EOF
Parse error. Emit the current tag token. Reconsume the EOF character in the data state.
Anything else
Append the current input character to the current attribute's name. Stay in the attribute name state.

When the user agent leaves the attribute name state (and before emitting the tag token, if appropriate), the complete attribute's name must be compared to the other attributes on the same token; if there is already an attribute on the token with the exact same name, then this is a parse error and the new attribute must be dropped, along with the value that gets associated with it (if any).

8.2.4.8 After attribute name state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the after attribute name state.
U+002F SOLIDUS (/)
Switch to the self-closing start tag state.
U+003D EQUALS SIGN (=)
Switch to the before attribute value state.
U+003E GREATER-THAN SIGN (>)
Emit the current tag token. Switch to the data state.
U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Start a new attribute in the current tag token. Set that attribute's name to the lowercase version of the current input character (add 0x0020 to the character's code point), and its value to the empty string. Switch to the attribute name state.
U+0022 QUOTATION MARK (")
U+0027 APOSTROPHE (')
Parse error. Treat it as per the "anything else" entry below.
EOF
Parse error. Emit the current tag token. Reconsume the EOF character in the data state.
Anything else
Start a new attribute in the current tag token. Set that attribute's name to the current input character, and its value to the empty string. Switch to the attribute name state.
8.2.4.9 Before attribute value state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the before attribute value state.
U+0022 QUOTATION MARK (")
Switch to the attribute value (double-quoted) state.
U+0026 AMPERSAND (&)
Switch to the attribute value (unquoted) state and reconsume this input character.
U+0027 APOSTROPHE (')
Switch to the attribute value (single-quoted) state.
U+003E GREATER-THAN SIGN (>)
Parse error. Emit the current tag token. Switch to the data state.
U+003D EQUALS SIGN (=)
Parse error. Treat it as per the "anything else" entry below.
EOF
Parse error. Emit the current tag token. Reconsume the character in the data state.
Anything else
Append the current input character to the current attribute's value. Switch to the attribute value (unquoted) state.
8.2.4.10 Attribute value (double-quoted) state

Consume the next input character:

U+0022 QUOTATION MARK (")
Switch to the after attribute value (quoted) state.
U+0026 AMPERSAND (&)
Switch to the character reference in attribute value state, with the additional allowed character being U+0022 QUOTATION MARK (").
EOF
Parse error. Emit the current tag token. Reconsume the character in the data state.
Anything else
Append the current input character to the current attribute's value. Stay in the attribute value (double-quoted) state.
8.2.4.11 Attribute value (single-quoted) state

Consume the next input character:

U+0027 APOSTROPHE (')
Switch to the after attribute value (quoted) state.
U+0026 AMPERSAND (&)
Switch to the character reference in attribute value state, with the additional allowed character being U+0027 APOSTROPHE (').
EOF
Parse error. Emit the current tag token. Reconsume the character in the data state.
Anything else
Append the current input character to the current attribute's value. Stay in the attribute value (single-quoted) state.
8.2.4.12 Attribute value (unquoted) state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Switch to the before attribute name state.
U+0026 AMPERSAND (&)
Switch to the character reference in attribute value state, with no additional allowed character.
U+003E GREATER-THAN SIGN (>)
Emit the current tag token. Switch to the data state.
U+0022 QUOTATION MARK (")
U+0027 APOSTROPHE (')
U+003D EQUALS SIGN (=)
Parse error. Treat it as per the "anything else" entry below.
EOF
Parse error. Emit the current tag token. Reconsume the character in the data state.
Anything else
Append the current input character to the current attribute's value. Stay in the attribute value (unquoted) state.
8.2.4.13 Character reference in attribute value state

Attempt to consume a character reference.

If nothing is returned, append a U+0026 AMPERSAND character to the current attribute's value.

Otherwise, append the returned character token to the current attribute's value.

Finally, switch back to the attribute value state that you were in when were switched into this state.

8.2.4.14 After attribute value (quoted) state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Switch to the before attribute name state.
U+002F SOLIDUS (/)
Switch to the self-closing start tag state.
U+003E GREATER-THAN SIGN (>)
Emit the current tag token. Switch to the data state.
EOF
Parse error. Emit the current tag token. Reconsume the EOF character in the data state.
Anything else
Parse error. Reconsume the character in the before attribute name state.
8.2.4.15 Self-closing start tag state

Consume the next input character:

U+003E GREATER-THAN SIGN (>)
Set the self-closing flag of the current tag token. Emit the current tag token. Switch to the data state.
EOF
Parse error. Emit the current tag token. Reconsume the EOF character in the data state.
Anything else
Parse error. Reconsume the character in the before attribute name state.
8.2.4.16 Bogus comment state

(This can only happen if the content model flag is set to the PCDATA state.)

Consume every character up to and including the first U+003E GREATER-THAN SIGN character (>) or the end of the file (EOF), whichever comes first. Emit a comment token whose data is the concatenation of all the characters starting from and including the character that caused the state machine to switch into the bogus comment state, up to and including the character immediately before the last consumed character (i.e. up to the character just before the U+003E or EOF character). (If the comment was started by the end of the file (EOF), the token is empty.)

Switch to the data state.

If the end of the file was reached, reconsume the EOF character.

8.2.4.17 Markup declaration open state

(This can only happen if the content model flag is set to the PCDATA state.)

If the next two characters are both U+002D HYPHEN-MINUS (-) characters, consume those two characters, create a comment token whose data is the empty string, and switch to the comment start state.

Otherwise, if the next seven characters are an ASCII case-insensitive match for the word "DOCTYPE", then consume those characters and switch to the DOCTYPE state.

Otherwise, if the insertion mode is "in foreign content" and the current node is not an element in the HTML namespace and the next seven characters are an ASCII case-sensitive match for the string "[CDATA[" (the five uppercase letters "CDATA" with a U+005B LEFT SQUARE BRACKET character before and after), then consume those characters and switch to the CDATA section state (which is unrelated to the content model flag's CDATA state).

Otherwise, this is a parse error. Switch to the bogus comment state. The next character that is consumed, if any, is the first character that will be in the comment.

8.2.4.18 Comment start state

Consume the next input character:

U+002D HYPHEN-MINUS (-)
Switch to the comment start dash state.
U+003E GREATER-THAN SIGN (>)
Parse error. Emit the comment token. Switch to the data state.
EOF
Parse error. Emit the comment token. Reconsume the EOF character in the data state.
Anything else
Append the input character to the comment token's data. Switch to the comment state.
8.2.4.19 Comment start dash state

Consume the next input character:

U+002D HYPHEN-MINUS (-)
Switch to the comment end state
U+003E GREATER-THAN SIGN (>)
Parse error. Emit the comment token. Switch to the data state.
EOF
Parse error. Emit the comment token. Reconsume the EOF character in the data state.
Anything else
Append a U+002D HYPHEN-MINUS (-) character and the input character to the comment token's data. Switch to the comment state.
8.2.4.20 Comment state

Consume the next input character:

U+002D HYPHEN-MINUS (-)
Switch to the comment end dash state
EOF
Parse error. Emit the comment token. Reconsume the EOF character in the data state.
Anything else
Append the input character to the comment token's data. Stay in the comment state.
8.2.4.21 Comment end dash state

Consume the next input character:

U+002D HYPHEN-MINUS (-)
Switch to the comment end state
EOF
Parse error. Emit the comment token. Reconsume the EOF character in the data state.
Anything else
Append a U+002D HYPHEN-MINUS (-) character and the input character to the comment token's data. Switch to the comment state.
8.2.4.22 Comment end state

Consume the next input character:

U+003E GREATER-THAN SIGN (>)
Emit the comment token. Switch to the data state.
U+002D HYPHEN-MINUS (-)
Parse error. Append a U+002D HYPHEN-MINUS (-) character to the comment token's data. Stay in the comment end state.
EOF
Parse error. Emit the comment token. Reconsume the EOF character in the data state.
Anything else
Parse error. Append two U+002D HYPHEN-MINUS (-) characters and the input character to the comment token's data. Switch to the comment state.
8.2.4.23 DOCTYPE state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Switch to the before DOCTYPE name state.
Anything else
Parse error. Reconsume the current character in the before DOCTYPE name state.
8.2.4.24 Before DOCTYPE name state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the before DOCTYPE name state.
U+003E GREATER-THAN SIGN (>)
Parse error. Create a new DOCTYPE token. Set its force-quirks flag to on. Emit the token. Switch to the data state.
U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Create a new DOCTYPE token. Set the token's name to the lowercase version of the input character (add 0x0020 to the character's code point). Switch to the DOCTYPE name state.
EOF
Parse error. Create a new DOCTYPE token. Set its force-quirks flag to on. Emit the token. Reconsume the EOF character in the data state.
Anything else
Create a new DOCTYPE token. Set the token's name to the current input character. Switch to the DOCTYPE name state.
8.2.4.25 DOCTYPE name state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Switch to the after DOCTYPE name state.
U+003E GREATER-THAN SIGN (>)
Emit the current DOCTYPE token. Switch to the data state.
U+0041 LATIN CAPITAL LETTER A through to U+005A LATIN CAPITAL LETTER Z
Append the lowercase version of the input character (add 0x0020 to the character's code point) to the current DOCTYPE token's name. Stay in the DOCTYPE name state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Append the current input character to the current DOCTYPE token's name. Stay in the DOCTYPE name state.
8.2.4.26 After DOCTYPE name state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the after DOCTYPE name state.
U+003E GREATER-THAN SIGN (>)
Emit the current DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else

If the six characters starting from the current input character are an ASCII case-insensitive match for the word "PUBLIC", then consume those characters and switch to the before DOCTYPE public identifier state.

Otherwise, if the six characters starting from the current input character are an ASCII case-insensitive match for the word "SYSTEM", then consume those characters and switch to the before DOCTYPE system identifier state.

Otherwise, this is the parse error. Set the DOCTYPE token's force-quirks flag to on. Switch to the bogus DOCTYPE state.

8.2.4.27 Before DOCTYPE public identifier state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the before DOCTYPE public identifier state.
U+0022 QUOTATION MARK (")
Set the DOCTYPE token's public identifier to the empty string (not missing), then switch to the DOCTYPE public identifier (double-quoted) state.
U+0027 APOSTROPHE (')
Set the DOCTYPE token's public identifier to the empty string (not missing), then switch to the DOCTYPE public identifier (single-quoted) state.
U+003E GREATER-THAN SIGN (>)
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Parse error. Set the DOCTYPE token's force-quirks flag to on. Switch to the bogus DOCTYPE state.
8.2.4.28 DOCTYPE public identifier (double-quoted) state

Consume the next input character:

U+0022 QUOTATION MARK (")
Switch to the after DOCTYPE public identifier state.
U+003E GREATER-THAN SIGN (>)
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Append the current input character to the current DOCTYPE token's public identifier. Stay in the DOCTYPE public identifier (double-quoted) state.
8.2.4.29 DOCTYPE public identifier (single-quoted) state

Consume the next input character:

U+0027 APOSTROPHE (')
Switch to the after DOCTYPE public identifier state.
U+003E GREATER-THAN SIGN (>)
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Append the current input character to the current DOCTYPE token's public identifier. Stay in the DOCTYPE public identifier (single-quoted) state.
8.2.4.30 After DOCTYPE public identifier state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the after DOCTYPE public identifier state.
U+0022 QUOTATION MARK (")
Set the DOCTYPE token's system identifier to the empty string (not missing), then switch to the DOCTYPE system identifier (double-quoted) state.
U+0027 APOSTROPHE (')
Set the DOCTYPE token's system identifier to the empty string (not missing), then switch to the DOCTYPE system identifier (single-quoted) state.
U+003E GREATER-THAN SIGN (>)
Emit the current DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Parse error. Set the DOCTYPE token's force-quirks flag to on. Switch to the bogus DOCTYPE state.
8.2.4.31 Before DOCTYPE system identifier state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the before DOCTYPE system identifier state.
U+0022 QUOTATION MARK (")
Set the DOCTYPE token's system identifier to the empty string (not missing), then switch to the DOCTYPE system identifier (double-quoted) state.
U+0027 APOSTROPHE (')
Set the DOCTYPE token's system identifier to the empty string (not missing), then switch to the DOCTYPE system identifier (single-quoted) state.
U+003E GREATER-THAN SIGN (>)
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Parse error. Set the DOCTYPE token's force-quirks flag to on. Switch to the bogus DOCTYPE state.
8.2.4.32 DOCTYPE system identifier (double-quoted) state

Consume the next input character:

U+0022 QUOTATION MARK (")
Switch to the after DOCTYPE system identifier state.
U+003E GREATER-THAN SIGN (>)
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Append the current input character to the current DOCTYPE token's system identifier. Stay in the DOCTYPE system identifier (double-quoted) state.
8.2.4.33 DOCTYPE system identifier (single-quoted) state

Consume the next input character:

U+0027 APOSTROPHE (')
Switch to the after DOCTYPE system identifier state.
U+003E GREATER-THAN SIGN (>)
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Append the current input character to the current DOCTYPE token's system identifier. Stay in the DOCTYPE system identifier (single-quoted) state.
8.2.4.34 After DOCTYPE system identifier state

Consume the next input character:

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
Stay in the after DOCTYPE system identifier state.
U+003E GREATER-THAN SIGN (>)
Emit the current DOCTYPE token. Switch to the data state.
EOF
Parse error. Set the DOCTYPE token's force-quirks flag to on. Emit that DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Parse error. Switch to the bogus DOCTYPE state. (This does not set the DOCTYPE token's force-quirks flag to on.)
8.2.4.35 Bogus DOCTYPE state

Consume the next input character:

U+003E GREATER-THAN SIGN (>)
Emit the DOCTYPE token. Switch to the data state.
EOF
Emit the DOCTYPE token. Reconsume the EOF character in the data state.
Anything else
Stay in the bogus DOCTYPE state.
8.2.4.36 CDATA section state

(This can only happen if the content model flag is set to the PCDATA state, and is unrelated to the content model flag's CDATA state.)

Consume every character up to the next occurrence of the three character sequence U+005D RIGHT SQUARE BRACKET U+005D RIGHT SQUARE BRACKET U+003E GREATER-THAN SIGN (]]>), or the end of the file (EOF), whichever comes first. Emit a series of character tokens consisting of all the characters consumed except the matching three character sequence at the end (if one was found before the end of the file).

Switch to the data state.

If the end of the file was reached, reconsume the EOF character.

8.2.4.37 Tokenizing character references

This section defines how to consume a character reference. This definition is used when parsing character references in text and in attributes.

The behavior depends on the identity of the next character (the one immediately after the U+0026 AMPERSAND character):

U+0009 CHARACTER TABULATION
U+000A LINE FEED (LF)
U+000C FORM FEED (FF)
U+0020 SPACE
U+003C LESS-THAN SIGN
U+0026 AMPERSAND
EOF
The additional allowed character, if there is one
Not a character reference. No characters are consumed, and nothing is returned. (This is not an error, either.)
U+0023 NUMBER SIGN (#)

Consume the U+0023 NUMBER SIGN.

The behavior further depends on the character after the U+0023 NUMBER SIGN:

U+0078 LATIN SMALL LETTER X
U+0058 LATIN CAPITAL LETTER X

Consume the X.

Follow the steps below, but using the range of characters U+0030 DIGIT ZERO through to U+0039 DIGIT NINE, U+0061 LATIN SMALL LETTER A through to U+0066 LATIN SMALL LETTER F, and U+0041 LATIN CAPITAL LETTER A, through to U+0046 LATIN CAPITAL LETTER F (in other words, 0-9, A-F, a-f).

When it comes to interpreting the number, interpret it as a hexadecimal number.

Anything else

Follow the steps below, but using the range of characters U+0030 DIGIT ZERO through to U+0039 DIGIT NINE (i.e. just 0-9).

When it comes to interpreting the number, interpret it as a decimal number.

Consume as many characters as match the range of characters given above.

If no characters match the range, then don't consume any characters (and unconsume the U+0023 NUMBER SIGN character and, if appropriate, the X character). This is a parse error; nothing is returned.

Otherwise, if the next character is a U+003B SEMICOLON, consume that too. If it isn't, there is a parse error.

If one or more characters match the range, then take them all and interpret the string of characters as a number (either hexadecimal or decimal as appropriate).

If that number is one of the numbers in the first column of the following table, then this is a parse error. Find the row with that number in the first column, and return a character token for the Unicode character given in the second column of that row.

Number Unicode character
0x0D U+000A LINE FEED (LF)
0x80 U+20AC EURO SIGN ('€')
0x81 U+FFFD REPLACEMENT CHARACTER
0x82 U+201A SINGLE LOW-9 QUOTATION MARK ('‚')
0x83 U+0192 LATIN SMALL LETTER F WITH HOOK ('ƒ')
0x84 U+201E DOUBLE LOW-9 QUOTATION MARK ('„')
0x85 U+2026 HORIZONTAL ELLIPSIS ('…')
0x86 U+2020 DAGGER ('†')
0x87 U+2021 DOUBLE DAGGER ('‡')
0x88 U+02C6 MODIFIER LETTER CIRCUMFLEX ACCENT ('ˆ')
0x89 U+2030 PER MILLE SIGN ('‰')
0x8A U+0160 LATIN CAPITAL LETTER S WITH CARON ('Š')
0x8B U+2039 SINGLE LEFT-POINTING ANGLE QUOTATION MARK ('‹')
0x8C U+0152 LATIN CAPITAL LIGATURE OE ('Œ')
0x8D U+FFFD REPLACEMENT CHARACTER
0x8E U+017D LATIN CAPITAL LETTER Z WITH CARON ('Ž')
0x8F U+FFFD REPLACEMENT CHARACTER
0x90 U+FFFD REPLACEMENT CHARACTER
0x91 U+2018 LEFT SINGLE QUOTATION MARK ('‘')
0x92 U+2019 RIGHT SINGLE QUOTATION MARK ('’')
0x93 U+201C LEFT DOUBLE QUOTATION MARK ('“')
0x94 U+201D RIGHT DOUBLE QUOTATION MARK ('”')
0x95 U+2022 BULLET ('•')
0x96 U+2013 EN DASH ('–')
0x97 U+2014 EM DASH ('—')
0x98 U+02DC SMALL TILDE ('˜')
0x99 U+2122 TRADE MARK SIGN ('™')
0x9A U+0161 LATIN SMALL LETTER S WITH CARON ('š')
0x9B U+203A SINGLE RIGHT-POINTING ANGLE QUOTATION MARK ('›')
0x9C U+0153 LATIN SMALL LIGATURE OE ('œ')
0x9D U+FFFD REPLACEMENT CHARACTER
0x9E U+017E LATIN SMALL LETTER Z WITH CARON ('ž')
0x9F U+0178 LATIN CAPITAL LETTER Y WITH DIAERESIS ('Ÿ')

Otherwise, if the number is in the range 0x0000 to 0x0008, 0x000E to 0x001F, 0x007F to 0x009F, 0xD800 to 0xDFFF, 0xFDD0 to 0xFDEF, or is one of 0x000B, 0xFFFE, 0xFFFF, 0x1FFFE, 0x1FFFF, 0x2FFFE, 0x2FFFF, 0x3FFFE, 0x3FFFF, 0x4FFFE, 0x4FFFF, 0x5FFFE, 0x5FFFF, 0x6FFFE, 0x6FFFF, 0x7FFFE, 0x7FFFF, 0x8FFFE, 0x8FFFF, 0x9FFFE, 0x9FFFF, 0xAFFFE, 0xAFFFF, 0xBFFFE, 0xBFFFF, 0xCFFFE, 0xCFFFF, 0xDFFFE, 0xDFFFF, 0xEFFFE, 0xEFFFF, 0xFFFFE, 0xFFFFF, 0x10FFFE, or 0x10FFFF, or is higher than 0x10FFFF, then this is a parse error; return a character token for the U+FFFD REPLACEMENT CHARACTER character instead.

Otherwise, return a character token for the Unicode character whose code point is that number.

Anything else

Consume the maximum number of characters possible, with the consumed characters matching one of the identifiers in the first column of the named character references table (in a case-sensitive manner).

If no match can be made, then this is a parse error. No characters are consumed, and nothing is returned.

If the last character matched is not a U+003B SEMICOLON (;), there is a parse error.

If the character reference is being consumed as part of an attribute, and the last character matched is not a U+003B SEMICOLON (;), and the next character is in the range U+0030 DIGIT ZERO to U+0039 DIGIT NINE, U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER Z, or U+0061 LATIN SMALL LETTER A to U+007A LATIN SMALL LETTER Z, then, for historical reasons, all the characters that were matched after the U+0026 AMPERSAND (&) must be unconsumed, and nothing is returned.

Otherwise, return a character token for the character corresponding to the character reference name (as given by the second column of the named character references table).

If the markup contains I'm &notit; I tell you, the character reference is parsed as "not", as in, I'm ¬it; I tell you. But if the markup was I'm &notin; I tell you, the character reference would be parsed as "notin;", resulting in I'm ∉ I tell you.

8.2.5 Tree construction

The input to the tree construction stage is a sequence of tokens from the tokenization stage. The tree construction stage is associated with a DOM Document object when a parser is created. The "output" of this stage consists of dynamically modifying or extending that document's DOM tree.

This specification does not define when an interactive user agent has to render the Document so that it is available to the user, or when it has to begin accepting user input.

As each token is emitted from the tokeniser, the user agent must process the token according to the rules given in the section corresponding to the current insertion mode.

When the steps below require the UA to insert a character into a node, if that node has a child immediately before where the character is to be inserted, and that child is a Text node, and that Text node was the last node that the parser inserted into the document, then the character must be appended to that Text node; otherwise, a new Text node whose data is just that character must be inserted in the appropriate place.

DOM mutation events must not fire for changes caused by the UA parsing the document. (Conceptually, the parser is not mutating the DOM, it is constructing it.) This includes the parsing of any content inserted using document.write() and document.writeln() calls. [DOM3EVENTS]

Not all of the tag names mentioned below are conformant tag names in this specification; many are included to handle legacy content. They still form part of the algorithm that implementations are required to implement to claim conformance.

The algorithm described below places no limit on the depth of the DOM tree generated, or on the length of tag names, attribute names, attribute values, text nodes, etc. While implementors are encouraged to avoid arbitrary limits, it is recognized that practical concerns will likely force user agents to impose nesting depths.

8.2.5.1 Creating and inserting elements

When the steps below require the UA to create an element for a token in a particular namespace, the UA must create a node implementing the interface appropriate for the element type corresponding to the tag name of the token in the given namespace (as given in the specification that defines that element, e.g. for an a element in the HTML namespace, this specification defines it to be the HTMLAnchorElement interface), with the tag name being the name of that element, with the node being in the given namespace, and with the attributes on the node being those given in the given token.

The interface appropriate for an element in the HTML namespace that is not defined in this specification is HTMLElement. The interface appropriate for an element in another namespace that is not defined by that namespace's specification is Element.

When a resettable element is created in this manner, its reset algorithm must be invoked once the attributes are set. (This initializes the element's value and checkedness based on the element's attributes.)


When the steps below require the UA to insert an HTML element for a token, the UA must first create an element for the token in the HTML namespace, and then append this node to the current node, and push it onto the stack of open elements so that it is the new current node.

The steps below may also require that the UA insert an HTML element in a particular place, in which case the UA must follow the same steps except that it must insert or append the new node in the location specified instead of appending it to the current node. (This happens in particular during the parsing of tables with invalid content.)

If an element created by the insert an HTML element algorithm is a form-associated element, and the form element pointer is not null, and the newly created element doesn't have a form attribute, the user agent must associate the newly created element with the form element pointed to by the form element pointer before inserting it wherever it is to be inserted.


When the steps below require the UA to insert a foreign element for a token, the UA must first create an element for the token in the given namespace, and then append this node to the current node, and push it onto the stack of open elements so that it is the new current node. If the newly created element has an xmlns attribute in the XMLNS namespace whose value is not exactly the same as the element's namespace, that is a parse error. Similarly, if the newly created element has an xmlns:xlink attribute in the XMLNS namespace whose value is not the XLink Namespace, that is a parse error.

When the steps below require the user agent to adjust MathML attributes for a token, then, if the token has an attribute named definitionurl, change its name to definitionURL (note the case difference).

XXXSVG

When the steps below require the user agent to adjust SVG attributes for a token, then, for each attribute on the token whose attribute name is one of the ones in the first column of the following table, change the attribute's name to the name given in the corresponding cell in the second column. (This fixes the case of SVG attributes that are not all lowercase.)

Attribute name on token Attribute name on element
attributename attributeName
attributetype attributeType
basefrequency baseFrequency
baseprofile baseProfile
calcmode calcMode
clippathunits clipPathUnits
contentscripttype contentScriptType
contentstyletype contentStyleType
diffuseconstant diffuseConstant
edgemode edgeMode
externalresourcesrequired externalResourcesRequired
filterres filterRes
filterunits filterUnits
glyphref glyphRef
gradienttransform gradientTransform
gradientunits gradientUnits
kernelmatrix kernelMatrix
kernelunitlength kernelUnitLength
keypoints keyPoints
keysplines keySplines
keytimes keyTimes
lengthadjust lengthAdjust
limitingconeangle limitingConeAngle
markerheight markerHeight
markerunits markerUnits
markerwidth markerWidth
maskcontentunits maskContentUnits
maskunits maskUnits
numoctaves numOctaves
pathlength pathLength
patterncontentunits patternContentUnits
patterntransform patternTransform
patternunits patternUnits
pointsatx pointsAtX
pointsaty pointsAtY
pointsatz pointsAtZ
preservealpha preserveAlpha
preserveaspectratio preserveAspectRatio
primitiveunits primitiveUnits
refx refX
refy refY
repeatcount repeatCount
repeatdur repeatDur
requiredextensions requiredExtensions
requiredfeatures requiredFeatures
specularconstant specularConstant
specularexponent specularExponent
spreadmethod spreadMethod
startoffset startOffset
stddeviation stdDeviation
stitchtiles stitchTiles
surfacescale surfaceScale
systemlanguage systemLanguage
tablevalues tableValues
targetx targetX
targety targetY
textlength textLength
viewbox viewBox
viewtarget viewTarget
xchannelselector xChannelSelector
ychannelselector yChannelSelector
zoomandpan zoomAndPan

When the steps below require the user agent to adjust foreign attributes for a token, then, if any of the attributes on the token match the strings given in the first column of the following table, let the attribute be a namespaced attribute, with the prefix being the string given in the corresponding cell in the second column, the local name being the string given in the corresponding cell in the third column, and the namespace being the namespace given in the corresponding cell in the fourth column. (This fixes the use of namespaced attributes, in particular xml:lang.)

Attribute name Prefix Local name Namespace
xlink:actuate xlink actuate XLink namespace
xlink:arcrole xlink arcrole XLink namespace
xlink:href xlink href XLink namespace
xlink:role xlink role XLink namespace
xlink:show xlink show XLink namespace
xlink:title xlink title XLink namespace
xlink:type xlink type XLink namespace
xml:base xml base XML namespace
xml:lang xml lang XML namespace
xml:space xml space XML namespace
xmlns (none) xmlns XMLNS namespace
xmlns:xlink xmlns xlink XMLNS namespace

The generic CDATA element parsing algorithm and the generic RCDATA element parsing algorithm consist of the following steps. These algorithms are always invoked in response to a start tag token.

  1. Insert an HTML element for the token.

  2. If the algorithm that was invoked is the generic CDATA element parsing algorithm, switch the tokeniser's content model flag to the CDATA state; otherwise the algorithm invoked was the generic RCDATA element parsing algorithm, switch the tokeniser's content model flag to the RCDATA state.

  3. Let the original insertion mode be the current insertion mode.

  4. Then, switch the insertion mode to "in CDATA/RCDATA".

8.2.5.2 Closing elements that have implied end tags

When the steps below require the UA to generate implied end tags, then, while the current node is a dd element, a dt element, an li element, an option element, an optgroup element, a p element, an rp element, or an rt element, the UA must pop the current node off the stack of open elements.

If a step requires the UA to generate implied end tags but lists an element to exclude from the process, then the UA must perform the above steps as if that element was not in the above list.

8.2.5.3 Foster parenting

Foster parenting happens when content is misnested in tables.

When a node node is to be foster parented, the node node must be inserted into the foster parent element, and the current table must be marked as tainted. (Once the current table has been tainted, whitespace characters are inserted into the foster parent element instead of the current node.)

The foster parent element is the parent element of the last table element in the stack of open elements, if there is a table element and it has such a parent element. If there is no table element in the stack of open elements (fragment case), then the foster parent element is the first element in the stack of open elements (the html element). Otherwise, if there is a table element in the stack of open elements, but the last table element in the stack of open elements has no parent, or its parent node is not an element, then the foster parent element is the element before the last table element in the stack of open elements.

If the foster parent element is the parent element of the last table element in the stack of open elements, then node must be inserted immediately before the last table element in the stack of open elements in the foster parent element; otherwise, node must be appended to the foster parent element.

8.2.5.4 The "initial" insertion mode

When the insertion mode is "initial", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Ignore the token.

A comment token

Append a Comment node to the Document object with the data attribute set to the data given in the comment token.

A DOCTYPE token

If the DOCTYPE token's name is not a case-sensitive match for the string "html", or if the token's public identifier is not missing, or if the token's system identifier is neither missing nor a case-sensitive match for the string "about:legacy-compat", then there is a parse error (this is the DOCTYPE parse error). Conformance checkers may, instead of reporting this error, switch to a conformance checking mode for another language (e.g. based on the DOCTYPE token a conformance checker could recognize that the document is an HTML4-era document, and defer to an HTML4 conformance checker.)

Append a DocumentType node to the Document node, with the name attribute set to the name given in the DOCTYPE token, or the empty string if the name was missing; the publicId attribute set to the public identifier given in the DOCTYPE token, or the empty string if the public identifier was missing; the systemId attribute set to the system identifier given in the DOCTYPE token, or the empty string if the system identifier was missing; and the other attributes specific to DocumentType objects set to null and empty lists as appropriate. Associate the DocumentType node with the Document object so that it is returned as the value of the doctype attribute of the Document object.

Then, if the DOCTYPE token matches one of the conditions in the following list, then set the document to quirks mode:

Otherwise, if the DOCTYPE token matches one of the conditions in the following list, then set the document to limited quirks mode:

The name, system identifier, and public identifier strings must be compared to the values given in the lists above in an ASCII case-insensitive manner. A system identifier whose value is the empty string is not considered missing for the purposes of the conditions above.

Then, switch the insertion mode to "before html".

Anything else

Parse error.

Set the document to quirks mode.

Switch the insertion mode to "before html", then reprocess the current token.

8.2.5.5 The "before html" insertion mode

When the insertion mode is "before html", tokens must be handled as follows:

A DOCTYPE token

Parse error. Ignore the token.

A comment token

Append a Comment node to the Document object with the data attribute set to the data given in the comment token.

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Ignore the token.

A start tag whose tag name is "html"

Create an element for the token in the HTML namespace. Append it to the Document object. Put this element in the stack of open elements.

If the Document is being loaded as part of navigation of a browsing context, then: if the newly created element has a manifest attribute, then resolve the value of that attribute to an absolute URL, relative to the newly created element, and if that is successful, run the application cache selection algorithm with the resulting absolute URL; otherwise, if there is no such attribute or resolving it fails, run the application cache selection algorithm with no manifest. The algorithm must be passed the Document object.

Switch the insertion mode to "before head".

Anything else

Create an html element. Append it to the Document object. Put this element in the stack of open elements.

If the Document is being loaded as part of navigation of a browsing context, then: run the application cache selection algorithm with no manifest, passing it the Document object.

Switch the insertion mode to "before head", then reprocess the current token.

Should probably make end tags be ignored, so that "</head><!-- --><html>" puts the comment before the root node (or should we?)

The root element can end up being removed from the Document object, e.g. by scripts; nothing in particular happens in such cases, content continues being appended to the nodes as described in the next section.

8.2.5.6 The "before head" insertion mode

When the insertion mode is "before head", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Ignore the token.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

A start tag whose tag name is "head"

Insert an HTML element for the token.

Set the head element pointer to the newly created head element.

Switch the insertion mode to "in head".

An end tag whose tag name is one of: "head", "body", "html", "br"

Act as if a start tag token with the tag name "head" and no attributes had been seen, then reprocess the current token.

Any other end tag

Parse error. Ignore the token.

Anything else

Act as if a start tag token with the tag name "head" and no attributes had been seen, then reprocess the current token.

This will result in an empty head element being generated, with the current token being reprocessed in the "after head" insertion mode.

8.2.5.7 The "in head" insertion mode

When the insertion mode is "in head", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Insert the character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

A start tag whose tag name is one of: "base", "command", "link"

Insert an HTML element for the token. Immediately pop the current node off the stack of open elements.

Acknowledge the token's self-closing flag, if it is set.

A start tag whose tag name is "meta"

Insert an HTML element for the token. Immediately pop the current node off the stack of open elements.

Acknowledge the token's self-closing flag, if it is set.

If the element has a charset attribute, and its value is a supported encoding, and the confidence is currently tentative, then change the encoding to the encoding given by the value of the charset attribute.

Otherwise, if the element has a content attribute, and applying the algorithm for extracting an encoding from a Content-Type to its value returns a supported encoding encoding, and the confidence is currently tentative, then change the encoding to the encoding encoding.

A start tag whose tag name is "title"

Follow the generic RCDATA element parsing algorithm.

A start tag whose tag name is "noscript", if the scripting flag is enabled
A start tag whose tag name is one of: "noframes", "style"

Follow the generic CDATA element parsing algorithm.

A start tag whose tag name is "noscript", if the scripting flag is disabled

Insert an HTML element for the token.

Switch the insertion mode to "in head noscript".

A start tag whose tag name is "script"
  1. Create an element for the token in the HTML namespace.

  2. Mark the element as being "parser-inserted".

    This ensures that, if the script is external, any document.write() calls in the script will execute in-line, instead of blowing the document away, as would happen in most other cases. It also prevents the script from executing until the end tag is seen.

  3. If the parser was originally created for the HTML fragment parsing algorithm, then mark the script element as "already executed". (fragment case)

  4. Append the new element to the current node and push it onto the stack of open elements.

  5. Switch the tokeniser's content model flag to the CDATA state.

  6. Let the original insertion mode be the current insertion mode.

  7. Switch the insertion mode to "in CDATA/RCDATA".

An end tag whose tag name is "head"

Pop the current node (which will be the head element) off the stack of open elements.

Switch the insertion mode to "after head".

An end tag whose tag name is one of: "body", "html", "br"

Act as described in the "anything else" entry below.

A start tag whose tag name is "head"
Any other end tag

Parse error. Ignore the token.

Anything else

Act as if an end tag token with the tag name "head" had been seen, and reprocess the current token.

In certain UAs, some elements don't trigger the "in body" mode straight away, but instead get put into the head. Do we want to copy that?

8.2.5.8 The "in head noscript" insertion mode

When the insertion mode is "in head noscript", tokens must be handled as follows:

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

An end tag whose tag name is "noscript"

Pop the current node (which will be a noscript element) from the stack of open elements; the new current node will be a head element.

Switch the insertion mode to "in head".

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE
A comment token
A start tag whose tag name is one of: "link", "meta", "noframes", "style"

Process the token using the rules for the "in head" insertion mode.

An end tag whose tag name is "br"

Act as described in the "anything else" entry below.

A start tag whose tag name is one of: "head", "noscript"
Any other end tag

Parse error. Ignore the token.

Anything else

Parse error. Act as if an end tag with the tag name "noscript" had been seen and reprocess the current token.

8.2.5.9 The "after head" insertion mode

When the insertion mode is "after head", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Insert the character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

A start tag whose tag name is "body"

Insert an HTML element for the token.

Switch the insertion mode to "in body".

A start tag whose tag name is "frameset"

Insert an HTML element for the token.

Switch the insertion mode to "in frameset".

A start tag token whose tag name is one of: "base", "link", "meta", "noframes", "script", "style", "title"

Parse error.

Push the node pointed to by the head element pointer onto the stack of open elements.

Process the token using the rules for the "in head" insertion mode.

Remove the node pointed to by the head element pointer from the stack of open elements.

An end tag whose tag name is one of: "body", "html", "br"

Act as described in the "anything else" entry below.

A start tag whose tag name is "head"
Any other end tag

Parse error. Ignore the token.

Anything else

Act as if a start tag token with the tag name "body" and no attributes had been seen, and then reprocess the current token.

8.2.5.10 The "in body" insertion mode

When the insertion mode is "in body", tokens must be handled as follows:

A character token

Reconstruct the active formatting elements, if any.

Insert the token's character into the current node.

If the token is not one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE, then set the frameset-ok flag to "not ok".

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Parse error. For each attribute on the token, check to see if the attribute is already present on the top element of the stack of open elements. If it is not, add the attribute and its corresponding value to that element.

A start tag token whose tag name is one of: "base", "command", "link", "meta", "noframes", "script", "style", "title"

Process the token using the rules for the "in head" insertion mode.

A start tag whose tag name is "body"

Parse error.

If the second element on the stack of open elements is not a body element, or, if the stack of open elements has only one node on it, then ignore the token. (fragment case)

Otherwise, for each attribute on the token, check to see if the attribute is already present on the body element (the second element) on the stack of open elements. If it is not, add the attribute and its corresponding value to that element.

A start tag whose tag name is "frameset"

Parse error.

If the second element on the stack of open elements is not a body element, or, if the stack of open elements has only one node on it, then ignore the token. (fragment case)

If the frameset-ok flag is set to "not ok", ignore the token.

Otherwise, run the following steps:

  1. Remove the second element on the stack of open elements from its parent node, if it has one.

  2. Pop all the nodes from the bottom of the stack of open elements, from the current node up to the root html element.

  3. Insert an HTML element for the token.

  4. Switch the insertion mode to "in frameset".

An end-of-file token

If there is a node in the stack of open elements that is not either a dd element, a dt element, an li element, a p element, a tbody element, a td element, a tfoot element, a th element, a thead element, a tr element, the body element, or the html element, then this is a parse error.

Stop parsing.

An end tag whose tag name is "body"

If the stack of open elements does not have a body element in scope, this is a parse error; ignore the token.

Otherwise, if there is a node in the stack of open elements that is not either a dd element, a dt element, an li element, an optgroup element, an option element, a p element, an rp element, an rt element, a tbody element, a td element, a tfoot element, a th element, a thead element, a tr element, the body element, or the html element, then this is a parse error.

Switch the insertion mode to "after body".

An end tag whose tag name is "html"

Act as if an end tag with tag name "body" had been seen, then, if that token wasn't ignored, reprocess the current token.

The fake end tag token here can only be ignored in the fragment case.

A start tag whose tag name is one of: "address", "article", "aside", "blockquote", "center", "datagrid", "details", "dialog", "dir", "div", "dl", "fieldset", "figure", "footer", "header", "menu", "nav", "ol", "p", "section", "ul"

If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

Insert an HTML element for the token.

A start tag whose tag name is one of: "h1", "h2", "h3", "h4", "h5", "h6"

If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

If the current node is an element whose tag name is one of "h1", "h2", "h3", "h4", "h5", or "h6", then this is a parse error; pop the current node off the stack of open elements.

Insert an HTML element for the token.

A start tag whose tag name is one of: "pre", "listing"

If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

Insert an HTML element for the token.

If the next token is a U+000A LINE FEED (LF) character token, then ignore that token and move on to the next one. (Newlines at the start of pre blocks are ignored as an authoring convenience.)

Set the frameset-ok flag to "not ok".

A start tag whose tag name is "form"

If the form element pointer is not null, then this is a parse error; ignore the token.

Otherwise:

If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

Insert an HTML element for the token, and set the form element pointer to point to the element created.

A start tag whose tag name is "li"

Run the following algorithm:

  1. Set the frameset-ok flag to "not ok".

  2. Initialize node to be the current node (the bottommost node of the stack).

  3. If node is an li element, then act as if an end tag with the tag name "li" had been seen, then jump to the last step.

  4. If node is not in the formatting category, and is not in the phrasing category, and is not an address, div, or p element, then jump to the last step.

  5. Otherwise, set node to the previous entry in the stack of open elements and return to step 2.

  6. This is the last step.

    If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

    Finally, insert an HTML element for the token.

A start tag whose tag name is one of: "dd", "dt"

Run the following algorithm:

  1. Set the frameset-ok flag to "not ok".

  2. Initialize node to be the current node (the bottommost node of the stack).

  3. If node is a dd or dt element, then act as if an end tag with the same tag name as node had been seen, then jump to the last step.

  4. If node is not in the formatting category, and is not in the phrasing category, and is not an address, div, or p element, then jump to the last step.

  5. Otherwise, set node to the previous entry in the stack of open elements and return to step 2.

  6. This is the last step.

    If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

    Finally, insert an HTML element for the token.

A start tag whose tag name is "plaintext"

If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

Insert an HTML element for the token.

Switch the content model flag to the PLAINTEXT state.

Once a start tag with the tag name "plaintext" has been seen, that will be the last token ever seen other than character tokens (and the end-of-file token), because there is no way to switch the content model flag out of the PLAINTEXT state.

An end tag whose tag name is one of: "address", "article", "aside", "blockquote", "center", "datagrid", "details", "dialog", "dir", "div", "dl", "fieldset", "figure", "footer", "header", "listing", "menu", "nav", "ol", "pre", "section", "ul"

If the stack of open elements does not have an element in scope with the same tag name as that of the token, then this is a parse error; ignore the token.

Otherwise, run these steps:

  1. Generate implied end tags.

  2. If the current node is not an element with the same tag name as that of the token, then this is a parse error.

  3. Pop elements from the stack of open elements until an element with the same tag name as the token has been popped from the stack.

An end tag whose tag name is "form"

Let node be the element that the form element pointer is set to.

Set the form element pointer to null.

If node is null or the stack of open elements does not have node in scope, then this is a parse error; ignore the token.

Otherwise, run these steps:

  1. Generate implied end tags.

  2. If the current node is not node, then this is a parse error.

  3. Remove node from the stack of open elements.

An end tag whose tag name is "p"

If the stack of open elements does not have an element in scope with the same tag name as that of the token, then this is a parse error; act as if a start tag with the tag name "p" had been seen, then reprocess the current token.

Otherwise, run these steps:

  1. Generate implied end tags, except for elements with the same tag name as the token.

  2. If the current node is not an element with the same tag name as that of the token, then this is a parse error.

  3. Pop elements from the stack of open elements until an element with the same tag name as the token has been popped from the stack.

An end tag whose tag name is one of: "dd", "dt", "li"

If the stack of open elements does not have an element in scope with the same tag name as that of the token, then this is a parse error; ignore the token.

Otherwise, run these steps:

  1. Generate implied end tags, except for elements with the same tag name as the token.

  2. If the current node is not an element with the same tag name as that of the token, then this is a parse error.

  3. Pop elements from the stack of open elements until an element with the same tag name as the token has been popped from the stack.

An end tag whose tag name is one of: "h1", "h2", "h3", "h4", "h5", "h6"

If the stack of open elements does not have an element in scope whose tag name is one of "h1", "h2", "h3", "h4", "h5", or "h6", then this is a parse error; ignore the token.

Otherwise, run these steps:

  1. Generate implied end tags.

  2. If the current node is not an element with the same tag name as that of the token, then this is a parse error.

  3. Pop elements from the stack of open elements until an element whose tag name is one of "h1", "h2", "h3", "h4", "h5", or "h6" has been popped from the stack.

An end tag whose tag name is "sarcasm"

Take a deep breath, then act as described in the "any other end tag" entry below.

A start tag whose tag name is "a"

If the list of active formatting elements contains an element whose tag name is "a" between the end of the list and the last marker on the list (or the start of the list if there is no marker on the list), then this is a parse error; act as if an end tag with the tag name "a" had been seen, then remove that element from the list of active formatting elements and the stack of open elements if the end tag didn't already remove it (it might not have if the element is not in table scope).

In the non-conforming stream <a href="a">a<table><a href="b">b</table>x, the first a element would be closed upon seeing the second one, and the "x" character would be inside a link to "b", not to "a". This is despite the fact that the outer a element is not in table scope (meaning that a regular </a> end tag at the start of the table wouldn't close the outer a element).

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token. Add that element to the list of active formatting elements.

A start tag whose tag name is one of: "b", "big", "code", "em", "font", "i", "s", "small", "strike", "strong", "tt", "u"

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token. Add that element to the list of active formatting elements.

A start tag whose tag name is "nobr"

Reconstruct the active formatting elements, if any.

If the stack of open elements has a nobr element in scope, then this is a parse error; act as if an end tag with the tag name "nobr" had been seen, then once again reconstruct the active formatting elements, if any.

Insert an HTML element for the token. Add that element to the list of active formatting elements.

An end tag whose tag name is one of: "a", "b", "big", "code", "em", "font", "i", "nobr", "s", "small", "strike", "strong", "tt", "u"

Follow these steps:

  1. Let the formatting element be the last element in the list of active formatting elements that:

    • is between the end of the list and the last scope marker in the list, if any, or the start of the list otherwise, and
    • has the same tag name as the token.

    If there is no such node, or, if that node is also in the stack of open elements but the element is not in scope, then this is a parse error; ignore the token, and abort these steps.

    Otherwise, if there is such a node, but that node is not in the stack of open elements, then this is a parse error; remove the element from the list, and abort these steps.

    Otherwise, there is a formatting element and that element is in the stack and is in scope. If the element is not the current node, this is a parse error. In any case, proceed with the algorithm as written in the following steps.

  2. Let the furthest block be the topmost node in the stack of open elements that is lower in the stack than the formatting element, and is not an element in the phrasing or formatting categories. There might not be one.

  3. If there is no furthest block, then the UA must skip the subsequent steps and instead just pop all the nodes from the bottom of the stack of open elements, from the current node up to and including the formatting element, and remove the formatting element from the list of active formatting elements.

  4. Let the common ancestor be the element immediately above the formatting element in the stack of open elements.

  5. Let a bookmark note the position of the formatting element in the list of active formatting elements relative to the elements on either side of it in the list.

  6. Let node and last node be the furthest block. Follow these steps:

    1. Let node be the element immediately above node in the stack of open elements.
    2. If node is not in the list of active formatting elements, then remove node from the stack of open elements and then go back to step 1.
    3. Otherwise, if node is the formatting element, then go to the next step in the overall algorithm.
    4. Otherwise, if last node is the furthest block, then move the aforementioned bookmark to be immediately after the node in the list of active formatting elements.
    5. Perform a shallow clone of node, replace the entry for node in the list of active formatting elements with an entry for the clone, replace the entry for node in the stack of open elements with an entry for the clone, and let node be the clone.
    6. Insert last node into node, first removing it from its previous parent node if any.
    7. Let last node be node.
    8. Return to step 1 of this inner set of steps.
  7. If the common ancestor node is a table, tbody, tfoot, thead, or tr element, then, foster parent whatever last node ended up being in the previous step, first removing it from its previous parent node if any.

    Otherwise, append whatever last node ended up being in the previous step to the common ancestor node, first removing it from its previous parent node if any.

  8. Perform a shallow clone of the formatting element.

  9. Take all of the child nodes of the furthest block and append them to the clone created in the last step.

  10. Append that clone to the furthest block.

  11. Remove the formatting element from the list of active formatting elements, and insert the clone into the list of active formatting elements at the position of the aforementioned bookmark.

  12. Remove the formatting element from the stack of open elements, and insert the clone into the stack of open elements immediately below the position of the furthest block in that stack.

  13. Jump back to step 1 in this series of steps.

The way these steps are defined, only elements in the formatting category ever get cloned by this algorithm.

Because of the way this algorithm causes elements to change parents, it has been dubbed the "adoption agency algorithm" (in contrast with other possibly algorithms for dealing with misnested content, which included the "incest algorithm", the "secret affair algorithm", and the "Heisenberg algorithm").

A start tag whose tag name is "button"

If the stack of open elements has a button element in scope, then this is a parse error; act as if an end tag with the tag name "button" had been seen, then reprocess the token.

Otherwise:

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token.

Insert a marker at the end of the list of active formatting elements.

Set the frameset-ok flag to "not ok".

A start tag token whose tag name is one of: "applet", "marquee", "object"

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token.

Insert a marker at the end of the list of active formatting elements.

Set the frameset-ok flag to "not ok".

An end tag token whose tag name is one of: "applet", "button", "marquee", "object"

If the stack of open elements does not have an element in scope with the same tag name as that of the token, then this is a parse error; ignore the token.

Otherwise, run these steps:

  1. Generate implied end tags.

  2. If the current node is not an element with the same tag name as that of the token, then this is a parse error.

  3. Pop elements from the stack of open elements until an element with the same tag name as the token has been popped from the stack.

  4. Clear the list of active formatting elements up to the last marker.
A start tag whose tag name is "table"

If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

Insert an HTML element for the token.

Set the frameset-ok flag to "not ok".

Switch the insertion mode to "in table".

A start tag whose tag name is one of: "area", "basefont", "bgsound", "br", "embed", "img", "input", "spacer", "wbr"

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token. Immediately pop the current node off the stack of open elements.

Acknowledge the token's self-closing flag, if it is set.

Set the frameset-ok flag to "not ok".

A start tag whose tag name is one of: "param", "source"

Insert an HTML element for the token. Immediately pop the current node off the stack of open elements.

Acknowledge the token's self-closing flag, if it is set.

A start tag whose tag name is "hr"

If the stack of open elements has a p element in scope, then act as if an end tag with the tag name "p" had been seen.

Insert an HTML element for the token. Immediately pop the current node off the stack of open elements.

Acknowledge the token's self-closing flag, if it is set.

Set the frameset-ok flag to "not ok".

A start tag whose tag name is "image"

Parse error. Change the token's tag name to "img" and reprocess it. (Don't ask.)

A start tag whose tag name is "isindex"

Parse error.

If the form element pointer is not null, then ignore the token.

Otherwise:

Acknowledge the token's self-closing flag, if it is set.

Act as if a start tag token with the tag name "form" had been seen.

If the token has an attribute called "action", set the action attribute on the resulting form element to the value of the "action" attribute of the token.

Act as if a start tag token with the tag name "hr" had been seen.

Act as if a start tag token with the tag name "p" had been seen.

Act as if a start tag token with the tag name "label" had been seen.

Act as if a stream of character tokens had been seen (see below for what they should say).

Act as if a start tag token with the tag name "input" had been seen, with all the attributes from the "isindex" token except "name", "action", and "prompt". Set the name attribute of the resulting input element to the value "isindex".

Act as if a stream of character tokens had been seen (see below for what they should say).

Act as if an end tag token with the tag name "label" had been seen.

Act as if an end tag token with the tag name "p" had been seen.

Act as if a start tag token with the tag name "hr" had been seen.

Act as if an end tag token with the tag name "form" had been seen.

If the token has an attribute with the name "prompt", then the first stream of characters must be the same string as given in that attribute, and the second stream of characters must be empty. Otherwise, the two streams of character tokens together should, together with the input element, express the equivalent of "This is a searchable index. Insert your search keywords here: (input field)" in the user's preferred language.

A start tag whose tag name is "textarea"
  1. Insert an HTML element for the token.

  2. If the next token is a U+000A LINE FEED (LF) character token, then ignore that token and move on to the next one. (Newlines at the start of textarea elements are ignored as an authoring convenience.)

  3. Switch the tokeniser's content model flag to the RCDATA state.

  4. Let the original insertion mode be the current insertion mode.

  5. Set the frameset-ok flag to "not ok".

  6. Switch the insertion mode to "in CDATA/RCDATA".

A start tag whose tag name is "xmp"

Reconstruct the active formatting elements, if any.

Set the frameset-ok flag to "not ok".

Follow the generic CDATA element parsing algorithm.

A start tag whose tag name is "iframe"

Set the frameset-ok flag to "not ok".

Follow the generic CDATA element parsing algorithm.

A start tag whose tag name is "noembed"
A start tag whose tag name is "noscript", if the scripting flag is enabled

Follow the generic CDATA element parsing algorithm.

A start tag whose tag name is "select"

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token.

Set the frameset-ok flag to "not ok".

If the insertion mode is one of in table", "in caption", "in column group", "in table body", "in row", or "in cell", then switch the insertion mode to "in select in table". Otherwise, switch the insertion mode to "in select".

A start tag whose tag name is one of: "optgroup", "option"

If the stack of open elements has an option element in scope, then act as if an end tag with the tag name "option" had been seen.

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token.

A start tag whose tag name is one of: "rp", "rt"

If the stack of open elements has a ruby element in scope, then generate implied end tags. If the current node is not then a ruby element, this is a parse error; pop all the nodes from the current node up to the node immediately before the bottommost ruby element on the stack of open elements.

Insert an HTML element for the token.

An end tag whose tag name is "br"

Parse error. Act as if a start tag token with the tag name "br" had been seen. Ignore the end tag token.

A start tag whose tag name is "math"

Reconstruct the active formatting elements, if any.

Adjust MathML attributes for the token. (This fixes the case of MathML attributes that are not all lowercase.)

Adjust foreign attributes for the token. (This fixes the use of namespaced attributes, in particular XLink.)

Insert a foreign element for the token, in the MathML namespace.

If the token has its self-closing flag set, pop the current node off the stack of open elements and acknowledge the token's self-closing flag.

Otherwise, let the secondary insertion mode be the current insertion mode, and then switch the insertion mode to "in foreign content".

XXXSVG
A start tag whose tag name is "svg"

Reconstruct the active formatting elements, if any.

Adjust SVG attributes for the token. (This fixes the case of SVG attributes that are not all lowercase.)

Adjust foreign attributes for the token. (This fixes the use of namespaced attributes, in particular XLink in SVG.)

Insert a foreign element for the token, in the SVG namespace.

If the token has its self-closing flag set, pop the current node off the stack of open elements and acknowledge the token's self-closing flag.

Otherwise, let the secondary insertion mode be the current insertion mode, and then switch the insertion mode to "in foreign content".

A start tag whose tag name is one of: "caption", "col", "colgroup", "frame", "head", "tbody", "td", "tfoot", "th", "thead", "tr"

Parse error. Ignore the token.

Any other start tag

Reconstruct the active formatting elements, if any.

Insert an HTML element for the token.

This element will be a phrasing element.

Any other end tag

Run the following steps:

  1. Initialize node to be the current node (the bottommost node of the stack).

  2. If node has the same tag name as the end tag token, then:

    1. Generate implied end tags.

    2. If the tag name of the end tag token does not match the tag name of the current node, this is a parse error.

    3. Pop all the nodes from the current node up to node, including node, then stop these steps.

  3. Otherwise, if node is in neither the formatting category nor the phrasing category, then this is a parse error; ignore the token, and abort these steps.

  4. Set node to the previous entry in the stack of open elements.

  5. Return to step 2.

8.2.5.11 The "in CDATA/RCDATA" insertion mode

When the insertion mode is "in CDATA/RCDATA", tokens must be handled as follows:

A character token

Insert the token's character into the current node.

An end-of-file token

Parse error.

If the current node is a script element, mark the script element as "already executed".

Pop the current node off the stack of open elements.

Switch the insertion mode to the original insertion mode and reprocess the current token.

An end tag whose tag name is "script"

Let script be the current node (which will be a script element).

Pop the current node off the stack of open elements.

Switch the insertion mode to the original insertion mode.

Let the old insertion point have the same value as the current insertion point. Let the insertion point be just before the next input character.

Increment the parser's script nesting level by one.

Run the script. This might cause some script to execute, which might cause new characters to be inserted into the tokeniser, and might cause the tokeniser to output more tokens, resulting in a reentrant invocation of the parser.

Decrement the parser's script nesting level by one. If the parser's script nesting level is zero, then set the parser pause flag to false.

Let the insertion point have the value of the old insertion point. (In other words, restore the insertion point to the value it had before the previous paragraph. This value might be the "undefined" value.)

At this stage, if there is a pending external script, then:

If the tree construction stage is being called reentrantly, say from a call to document.write():

Set the parser pause flag to true, and abort the processing of any nested invocations of the tokeniser, yielding control back to the caller. (Tokenization will resume when the caller returns to the "outer" tree construction stage.)

Otherwise:

Follow these steps:

  1. Let the script be the pending external script. There is no longer a pending external script.

  2. Pause until the script has completed loading.

  3. Let the insertion point be just before the next input character.

  4. Execute the script.

  5. Let the insertion point be undefined again.

  6. If there is once again a pending external script, then repeat these steps from step 1.

Any other end tag

Pop the current node off the stack of open elements.

Switch the insertion mode to the original insertion mode.

8.2.5.12 The "in table" insertion mode

When the insertion mode is "in table", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

If the current table is tainted, then act as described in the "anything else" entry below.

Otherwise, insert the character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "caption"

Clear the stack back to a table context. (See below.)

Insert a marker at the end of the list of active formatting elements.

Insert an HTML element for the token, then switch the insertion mode to "in caption".

A start tag whose tag name is "colgroup"

Clear the stack back to a table context. (See below.)

Insert an HTML element for the token, then switch the insertion mode to "in column group".

A start tag whose tag name is "col"

Act as if a start tag token with the tag name "colgroup" had been seen, then reprocess the current token.

A start tag whose tag name is one of: "tbody", "tfoot", "thead"

Clear the stack back to a table context. (See below.)

Insert an HTML element for the token, then switch the insertion mode to "in table body".

A start tag whose tag name is one of: "td", "th", "tr"

Act as if a start tag token with the tag name "tbody" had been seen, then reprocess the current token.

A start tag whose tag name is "table"

Parse error. Act as if an end tag token with the tag name "table" had been seen, then, if that token wasn't ignored, reprocess the current token.

The fake end tag token here can only be ignored in the fragment case.

An end tag whose tag name is "table"

If the stack of open elements does not have an element in table scope with the same tag name as the token, this is a parse error. Ignore the token. (fragment case)

Otherwise:

Pop elements from this stack until a table element has been popped from the stack.

Reset the insertion mode appropriately.

An end tag whose tag name is one of: "body", "caption", "col", "colgroup", "html", "tbody", "td", "tfoot", "th", "thead", "tr"

Parse error. Ignore the token.

A start tag whose tag name is one of: "style", "script"

If the current table is tainted then act as described in the "anything else" entry below.

Otherwise, process the token using the rules for the "in head" insertion mode.

A start tag whose tag name is "input"

If the token does not have an attribute with the name "type", or if it does, but that attribute's value is not an ASCII case-insensitive match for the string "hidden", or, if the current table is tainted, then: act as described in the "anything else" entry below.

Otherwise:

Parse error.

Insert an HTML element for the token.

Pop that input element off the stack of open elements.

An end-of-file token

If the current node is not the root html element, then this is a parse error.

It can only be the current node in the fragment case.

Stop parsing.

Anything else

Parse error. Process the token using the rules for the "in body" insertion mode, except that if the current node is a table, tbody, tfoot, thead, or tr element, then, whenever a node would be inserted into the current node, it must instead be foster parented.

When the steps above require the UA to clear the stack back to a table context, it means that the UA must, while the current node is not a table element or an html element, pop elements from the stack of open elements.

The current node being an html element after this process is a fragment case.

8.2.5.13 The "in caption" insertion mode

When the insertion mode is "in caption", tokens must be handled as follows:

An end tag whose tag name is "caption"

If the stack of open elements does not have an element in table scope with the same tag name as the token, this is a parse error. Ignore the token. (fragment case)

Otherwise:

Generate implied end tags.

Now, if the current node is not a caption element, then this is a parse error.

Pop elements from this stack until a caption element has been popped from the stack.

Clear the list of active formatting elements up to the last marker.

Switch the insertion mode to "in table".

A start tag whose tag name is one of: "caption", "col", "colgroup", "tbody", "td", "tfoot", "th", "thead", "tr"
An end tag whose tag name is "table"

Parse error. Act as if an end tag with the tag name "caption" had been seen, then, if that token wasn't ignored, reprocess the current token.

The fake end tag token here can only be ignored in the fragment case.

An end tag whose tag name is one of: "body", "col", "colgroup", "html", "tbody", "td", "tfoot", "th", "thead", "tr"

Parse error. Ignore the token.

Anything else

Process the token using the rules for the "in body" insertion mode.

8.2.5.14 The "in column group" insertion mode

When the insertion mode is "in column group", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Insert the character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

A start tag whose tag name is "col"

Insert an HTML element for the token. Immediately pop the current node off the stack of open elements.

Acknowledge the token's self-closing flag, if it is set.

An end tag whose tag name is "colgroup"

If the current node is the root html element, then this is a parse error; ignore the token. (fragment case)

Otherwise, pop the current node (which will be a colgroup element) from the stack of open elements. Switch the insertion mode to "in table".

An end tag whose tag name is "col"

Parse error. Ignore the token.

An end-of-file token

If the current node is the root html element, then stop parsing. (fragment case)

Otherwise, act as described in the "anything else" entry below.

Anything else

Act as if an end tag with the tag name "colgroup" had been seen, and then, if that token wasn't ignored, reprocess the current token.

The fake end tag token here can only be ignored in the fragment case.

8.2.5.15 The "in table body" insertion mode

When the insertion mode is "in table body", tokens must be handled as follows:

A start tag whose tag name is "tr"

Clear the stack back to a table body context. (See below.)

Insert an HTML element for the token, then switch the insertion mode to "in row".

A start tag whose tag name is one of: "th", "td"

Parse error. Act as if a start tag with the tag name "tr" had been seen, then reprocess the current token.

An end tag whose tag name is one of: "tbody", "tfoot", "thead"

If the stack of open elements does not have an element in table scope with the same tag name as the token, this is a parse error. Ignore the token.

Otherwise:

Clear the stack back to a table body context. (See below.)

Pop the current node from the stack of open elements. Switch the insertion mode to "in table".

A start tag whose tag name is one of: "caption", "col", "colgroup", "tbody", "tfoot", "thead"
An end tag whose tag name is "table"

If the stack of open elements does not have a tbody, thead, or tfoot element in table scope, this is a parse error. Ignore the token. (fragment case)

Otherwise:

Clear the stack back to a table body context. (See below.)

Act as if an end tag with the same tag name as the current node ("tbody", "tfoot", or "thead") had been seen, then reprocess the current token.

An end tag whose tag name is one of: "body", "caption", "col", "colgroup", "html", "td", "th", "tr"

Parse error. Ignore the token.

Anything else

Process the token using the rules for the "in table" insertion mode.

When the steps above require the UA to clear the stack back to a table body context, it means that the UA must, while the current node is not a tbody, tfoot, thead, or html element, pop elements from the stack of open elements.

The current node being an html element after this process is a fragment case.

8.2.5.16 The "in row" insertion mode

When the insertion mode is "in row", tokens must be handled as follows:

A start tag whose tag name is one of: "th", "td"

Clear the stack back to a table row context. (See below.)

Insert an HTML element for the token, then switch the insertion mode to "in cell".

Insert a marker at the end of the list of active formatting elements.

An end tag whose tag name is "tr"

If the stack of open elements does not have an element in table scope with the same tag name as the token, this is a parse error. Ignore the token. (fragment case)

Otherwise:

Clear the stack back to a table row context. (See below.)

Pop the current node (which will be a tr element) from the stack of open elements. Switch the insertion mode to "in table body".

A start tag whose tag name is one of: "caption", "col", "colgroup", "tbody", "tfoot", "thead", "tr"
An end tag whose tag name is "table"

Act as if an end tag with the tag name "tr" had been seen, then, if that token wasn't ignored, reprocess the current token.

The fake end tag token here can only be ignored in the fragment case.

An end tag whose tag name is one of: "tbody", "tfoot", "thead"

If the stack of open elements does not have an element in table scope with the same tag name as the token, this is a parse error. Ignore the token.

Otherwise, act as if an end tag with the tag name "tr" had been seen, then reprocess the current token.

An end tag whose tag name is one of: "body", "caption", "col", "colgroup", "html", "td", "th"

Parse error. Ignore the token.

Anything else

Process the token using the rules for the "in table" insertion mode.

When the steps above require the UA to clear the stack back to a table row context, it means that the UA must, while the current node is not a tr element or an html element, pop elements from the stack of open elements.

The current node being an html element after this process is a fragment case.

8.2.5.17 The "in cell" insertion mode

When the insertion mode is "in cell", tokens must be handled as follows:

An end tag whose tag name is one of: "td", "th"

If the stack of open elements does not have an element in table scope with the same tag name as that of the token, then this is a parse error and the token must be ignored.

Otherwise:

Generate implied end tags.

Now, if the current node is not an element with the same tag name as the token, then this is a parse error.

Pop elements from this stack until an element with the same tag name as the token has been popped from the stack.

Clear the list of active formatting elements up to the last marker.

Switch the insertion mode to "in row". (The current node will be a tr element at this point.)

A start tag whose tag name is one of: "caption", "col", "colgroup", "tbody", "td", "tfoot", "th", "thead", "tr"

If the stack of open elements does not have a td or th element in table scope, then this is a parse error; ignore the token. (fragment case)

Otherwise, close the cell (see below) and reprocess the current token.

An end tag whose tag name is one of: "body", "caption", "col", "colgroup", "html"

Parse error. Ignore the token.

An end tag whose tag name is one of: "table", "tbody", "tfoot", "thead", "tr"

If the stack of open elements does not have an element in table scope with the same tag name as that of the token (which can only happen for "tbody", "tfoot" and "thead", or, in the fragment case), then this is a parse error and the token must be ignored.

Otherwise, close the cell (see below) and reprocess the current token.

Anything else

Process the token using the rules for the "in body" insertion mode.

Where the steps above say to close the cell, they mean to run the following algorithm:

  1. If the stack of open elements has a td element in table scope, then act as if an end tag token with the tag name "td" had been seen.

  2. Otherwise, the stack of open elements will have a th element in table scope; act as if an end tag token with the tag name "th" had been seen.

The stack of open elements cannot have both a td and a th element in table scope at the same time, nor can it have neither when the insertion mode is "in cell".

8.2.5.18 The "in select" insertion mode

When the insertion mode is "in select", tokens must be handled as follows:

A character token

Insert the token's character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

A start tag whose tag name is "option"

If the current node is an option element, act as if an end tag with the tag name "option" had been seen.

Insert an HTML element for the token.

A start tag whose tag name is "optgroup"

If the current node is an option element, act as if an end tag with the tag name "option" had been seen.

If the current node is an optgroup element, act as if an end tag with the tag name "optgroup" had been seen.

Insert an HTML element for the token.

An end tag whose tag name is "optgroup"

First, if the current node is an option element, and the node immediately before it in the stack of open elements is an optgroup element, then act as if an end tag with the tag name "option" had been seen.

If the current node is an optgroup element, then pop that node from the stack of open elements. Otherwise, this is a parse error; ignore the token.

An end tag whose tag name is "option"

If the current node is an option element, then pop that node from the stack of open elements. Otherwise, this is a parse error; ignore the token.

An end tag whose tag name is "select"

If the stack of open elements does not have an element in table scope with the same tag name as the token, this is a parse error. Ignore the token. (fragment case)

Otherwise:

Pop elements from the stack of open elements until a select element has been popped from the stack.

Reset the insertion mode appropriately.

A start tag whose tag name is "select"

Parse error. Act as if the token had been an end tag with the tag name "select" instead.

A start tag whose tag name is one of: "input", "textarea"

Parse error. Act as if an end tag with the tag name "select" had been seen, and reprocess the token.

A start tag token whose tag name is "script"

Process the token using the rules for the "in head" insertion mode.

An end-of-file token

If the current node is not the root html element, then this is a parse error.

It can only be the current node in the fragment case.

Stop parsing.

Anything else

Parse error. Ignore the token.

8.2.5.19 The "in select in table" insertion mode

When the insertion mode is "in select in table", tokens must be handled as follows:

A start tag whose tag name is one of: "caption", "table", "tbody", "tfoot", "thead", "tr", "td", "th"

Parse error. Act as if an end tag with the tag name "select" had been seen, and reprocess the token.

An end tag whose tag name is one of: "caption", "table", "tbody", "tfoot", "thead", "tr", "td", "th"

Parse error.

If the stack of open elements has an element in table scope with the same tag name as that of the token, then act as if an end tag with the tag name "select" had been seen, and reprocess the token. Otherwise, ignore the token.

Anything else

Process the token using the rules for the "in select" insertion mode.

8.2.5.20 The "in foreign content" insertion mode

When the insertion mode is "in foreign content", tokens must be handled as follows:

A character token

Insert the token's character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

XXXSVG need to define processing for to match HTML5's processing

A start tag whose tag name is neither "mglyph" nor "malignmark", if the current node is an mi element in the MathML namespace.
A start tag whose tag name is neither "mglyph" nor "malignmark", if the current node is an mo element in the MathML namespace.
A start tag whose tag name is neither "mglyph" nor "malignmark", if the current node is an mn element in the MathML namespace.
A start tag whose tag name is neither "mglyph" nor "malignmark", if the current node is an ms element in the MathML namespace.
A start tag whose tag name is neither "mglyph" nor "malignmark", if the current node is an mtext element in the MathML namespace.
XXXSVG
A start tag whose tag name is "svg", if the current node is an annotation-xml element in the MathML namespace.
A start tag, if the current node is a foreignObject element in the SVG namespace.
A start tag, if the current node is a desc element in the SVG namespace.
A start tag, if the current node is a title element in the SVG namespace.
A start tag, if the current node is an element in the HTML namespace.
An end tag

Process the token using the rules for the secondary insertion mode.

If, after doing so, the insertion mode is still "in foreign content", but there is no element in scope that has a namespace other than the HTML namespace, switch the insertion mode to the secondary insertion mode.

A start tag whose tag name is one of: "b", "big", "blockquote", "body", "br", "center", "code", "dd", "div", "dl", "dt", "em", "embed", "h1", "h2", "h3", "h4", "h5", "h6", "head", "hr", "i", "img", "li", "listing", "menu", "meta", "nobr", "ol", "p", "pre", "ruby", "s", "small", "span", "strong", "strike", "sub", "sup", "table", "tt", "u", "ul", "var"
A start tag whose tag name is "font", if the token has any attributes named "color", "face", or "size"
An end-of-file token

Parse error.

Pop elements from the stack of open elements until the current node is in the HTML namespace.

Switch the insertion mode to the secondary insertion mode, and reprocess the token.

Any other start tag

If the current node is an element in the MathML namespace, adjust MathML attributes for the token. (This fixes the case of MathML attributes that are not all lowercase.)

XXXSVG

If the current node is an element in the SVG namespace, and the token's tag name is one of the ones in the first column of the following table, change the tag name to the name given in the corresponding cell in the second column. (This fixes the case of SVG elements that are not all lowercase.)

Tag name Element name
altglyph altGlyph
altglyphdef altGlyphDef
altglyphitem altGlyphItem
animatecolor animateColor
animatemotion animateMotion
animatetransform animateTransform
clippath clipPath
feblend feBlend
fecolormatrix feColorMatrix
fecomponenttransfer feComponentTransfer
fecomposite feComposite
feconvolvematrix feConvolveMatrix
fediffuselighting feDiffuseLighting
fedisplacementmap feDisplacementMap
fedistantlight feDistantLight
feflood feFlood
fefunca feFuncA
fefuncb feFuncB
fefuncg feFuncG
fefuncr feFuncR
fegaussianblur feGaussianBlur
feimage feImage
femerge feMerge
femergenode feMergeNode
femorphology feMorphology
feoffset feOffset
fepointlight fePointLight
fespecularlighting feSpecularLighting
fespotlight feSpotLight
fetile feTile
feturbulence feTurbulence
foreignobject foreignObject
glyphref glyphRef
lineargradient linearGradient
radialgradient radialGradient solidcolor solidColor (SVG 1.2)- ->
textpath textPath

If the current node is an element in the SVG namespace, adjust SVG attributes for the token. (This fixes the case of SVG attributes that are not all lowercase.)

Adjust foreign attributes for the token. (This fixes the use of namespaced attributes, in particular XLink in SVG.)

Insert a foreign element for the token, in the same namespace as the current node.

If the token has its self-closing flag set, pop the current node off the stack of open elements and acknowledge the token's self-closing flag.

8.2.5.21 The "after body" insertion mode

When the insertion mode is "after body", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Process the token using the rules for the "in body" insertion mode.

A comment token

Append a Comment node to the first element in the stack of open elements (the html element), with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

An end tag whose tag name is "html"

If the parser was originally created as part of the HTML fragment parsing algorithm, this is a parse error; ignore the token. (fragment case)

Otherwise, switch the insertion mode to "after after body".

An end-of-file token

Stop parsing.

Anything else

Parse error. Switch the insertion mode to "in body" and reprocess the token.

8.2.5.22 The "in frameset" insertion mode

When the insertion mode is "in frameset", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Insert the character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

A start tag whose tag name is "frameset"

Insert an HTML element for the token.

An end tag whose tag name is "frameset"

If the current node is the root html element, then this is a parse error; ignore the token. (fragment case)

Otherwise, pop the current node from the stack of open elements.

If the parser was not originally created as part of the HTML fragment parsing algorithm (fragment case), and the current node is no longer a frameset element, then switch the insertion mode to "after frameset".

A start tag whose tag name is "frame"

Insert an HTML element for the token. Immediately pop the current node off the stack of open elements.

Acknowledge the token's self-closing flag, if it is set.

A start tag whose tag name is "noframes"

Process the token using the rules for the "in head" insertion mode.

An end-of-file token

If the current node is not the root html element, then this is a parse error.

It can only be the current node in the fragment case.

Stop parsing.

Anything else

Parse error. Ignore the token.

8.2.5.23 The "after frameset" insertion mode

When the insertion mode is "after frameset", tokens must be handled as follows:

A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE

Insert the character into the current node.

A comment token

Append a Comment node to the current node with the data attribute set to the data given in the comment token.

A DOCTYPE token

Parse error. Ignore the token.

A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

An end tag whose tag name is "html"

Switch the insertion mode to "after after frameset".

A start tag whose tag name is "noframes"

Process the token using the rules for the "in head" insertion mode.

An end-of-file token

Stop parsing.

Anything else

Parse error. Ignore the token.

This doesn't handle UAs that don't support frames, or that do support frames but want to show the NOFRAMES content. Supporting the former is easy; supporting the latter is harder.

8.2.5.24 The "after after body" insertion mode

When the insertion mode is "after after body", tokens must be handled as follows:

A comment token

Append a Comment node to the Document object with the data attribute set to the data given in the comment token.

A DOCTYPE token
A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE
A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

An end-of-file token

Stop parsing.

Anything else

Parse error. Switch the insertion mode to "in body" and reprocess the token.

8.2.5.25 The "after after frameset" insertion mode

When the insertion mode is "after after frameset", tokens must be handled as follows:

A comment token

Append a Comment node to the Document object with the data attribute set to the data given in the comment token.

A DOCTYPE token
A character token that is one of U+0009 CHARACTER TABULATION, U+000A LINE FEED (LF), U+000C FORM FEED (FF), or U+0020 SPACE
A start tag whose tag name is "html"

Process the token using the rules for the "in body" insertion mode.

An end-of-file token

Stop parsing.

A start tag whose tag name is "noframes"

Process the token using the rules for the "in head" insertion mode.

Anything else

Parse error. Ignore the token.

8.2.6 The end

Once the user agent stops parsing the document, the user agent must follow the steps in this section.

First, the current document readiness must be set to "interactive".

Then, the rules for when a script completes loading start applying (script execution is no longer managed by the parser).

If any of the scripts in the list of scripts that will execute as soon as possible have completed loading, or if the list of scripts that will execute asynchronously is not empty and the first script in that list has completed loading, then the user agent must act as if those scripts just completed loading, following the rules given for that in the script element definition.

Then, if the list of scripts that will execute when the document has finished parsing is not empty, and the first item in this list has already completed loading, then the user agent must act as if that script just finished loading.

By this point, there will be no scripts that have loaded but have not yet been executed.

The user agent must then fire a simple event called DOMContentLoaded at the Document.

Once everything that delays the load event has completed, the user agent must run the following steps:

  1. Queue a task to set the current document readiness to "complete".
  2. If the Document is in a browsing context, then queue a task to fire a load event at the Document's Window object.
  3. If the Document has a pending state object, then queue a task to fire a popstate event in no namespace on the Document's Window object using the PopStateEvent interface, with the state attribute set to the current value of the pending state object. This event must bubble but not be cancelable and has no default action.

The task source for these tasks is the DOM manipulation task source.

delaying the load event for things like image loads allows for intranet port scans (even without javascript!). Should we really encode that into the spec?

8.2.7 Coercing an HTML DOM into an infoset

When an application uses an HTML parser in conjunction with an XML pipeline, it is possible that the constructed DOM is not compatible with the XML tool chain in certain subtle ways. For example, an XML toolchain might not be able to represent attributes with the name xmlns, since they conflict with the Namespaces in XML syntax. There is also some data that the HTML parser generates that isn't included in the DOM itself. This section specifies some rules for handling these issues.

If the XML API being used doesn't support DOCTYPEs, the tool may drop DOCTYPEs altogether.

If the XML API doesn't support attributes in no namespace that are named "xmlns", attributes whose names start with "xmlns:", or attributes in the XMLNS namespace, then the tool may drop such attributes.

The tool may annotate the output with any namespace declarations required for proper operation.

If the XML API being used restricts the allowable characters in the local names of elements and attributes, then the tool may map all element and attribute local names that the API wouldn't support to a set of names that are allowed, by replacing any character that isn't supported with the uppercase letter U and the six digits of the character's Unicode codepoint when expressed in hexadecimal, using digits 0-9 and capital letters A-F as the symbols, in increasing numeric order.

For example, the element name foo<bar, which can be output by the HTML parser, though it is neither a legal HTML element name nor a well-formed XML element name, would be converted into fooU00003Cbar, which is a well-formed XML element name (though it's still not legal in HTML by any means).

As another example, consider the attribute xlink:href. Used on a MathML element, it becomes, after being adjusted, an attribute with a prefix "xlink" and a local name "href". However, used on an HTML element, it becomes an attribute with no prefix and the local name "xlink:href", which is not a valid NCName, and thus might not be accepted by an XML API. It could thus get converted, becoming "xlinkU00003Ahref".

The resulting names from this conversion conveniently can't clash with any attribute generated by the HTML parser, since those are all either lowercase or those listed in the adjust foreign attributes algorithm's table.

If the XML API restricts comments from having two consecutive U+002D HYPHEN-MINUS characters (--), the tool may insert a single U+0020 SPACE character between any such offending characters.

If the XML API restricts comments from ending in a U+002D HYPHEN-MINUS character (-), the tool may insert a single U+0020 SPACE character at the end of such comments.

If the XML API restricts allowed characters in character data, the tool may replace any U+000C FORM FEED (FF) character with a U+0020 SPACE character, and any other literal non-XML character with a U+FFFD REPLACEMENT CHARACTER.

If the tool has no way to convey out-of-band information, then the tool may drop the following information:

The mutations allowed by this section apply after the HTML parser's rules have been applied. For example, a <a::> start tag will be closed by a </a::> end tag, and never by a </aU00003AU00003A> end tag, even if the user agent is using the rules above to then generate an actual element in the DOM with the name aU00003AU00003A for that start tag.

8.3 Namespaces

The HTML namespace is: http://www.w3.org/1999/xhtml

The MathML namespace is: http://www.w3.org/1998/Math/MathML

The SVG namespace is: http://www.w3.org/2000/svg

The XLink namespace is: http://www.w3.org/1999/xlink

The XML namespace is: http://www.w3.org/XML/1998/namespace

The XMLNS namespace is: http://www.w3.org/2000/xmlns/


Data mining tools and other user agents that perform operations on text/html content without running scripts, evaluating CSS or XPath expressions, or otherwise exposing the resulting DOM to arbitrary content, may "support namespaces" by just asserting that their DOM node analogues are in certain namespaces, without actually exposing the above strings.

8.4 Serializing HTML fragments

The following steps form the HTML fragment serialization algorithm. The algorithm takes as input a DOM Element or Document, referred to as the node, and either returns a string or raises an exception.

This algorithm serializes the children of the node being serialized, not the node itself.

  1. Let s be a string, and initialize it to the empty string.

  2. For each child node of the node, in tree order, run the following steps:

    1. Let current node be the child node being processed.

    2. Append the appropriate string from the following list to s:

      If current node is an Element

      Append a U+003C LESS-THAN SIGN (<) character, followed by the element's tag name. (For nodes created by the HTML parser, Document.createElement(), or Document.renameNode(), the tag name will be lowercase.)

      For each attribute that the element has, append a U+0020 SPACE character, the attribute's name (which, for attributes set by the HTML parser or by Element.setAttributeNode() or Element.setAttribute(), will be lowercase), a U+003D EQUALS SIGN (=) character, a U+0022 QUOTATION MARK (") character, the attribute's value, escaped as described below in attribute mode, and a second U+0022 QUOTATION MARK (") character.

      While the exact order of attributes is UA-defined, and may depend on factors such as the order that the attributes were given in the original markup, the sort order must be stable, such that consecutive invocations of this algorithm serialize an element's attributes in the same order.

      Append a U+003E GREATER-THAN SIGN (>) character.

      If current node is an area, base, basefont, bgsound, br, col, embed, frame, hr, img, input, link, meta, param, spacer, or wbr element, then continue on to the next child node at this point.

      If current node is a pre, textarea, or listing element, append a U+000A LINE FEED (LF) character.

      Append the value of running the HTML fragment serialization algorithm on the current node element (thus recursing into this algorithm for that element), followed by a U+003C LESS-THAN SIGN (<) character, a U+002F SOLIDUS (/) character, the element's tag name again, and finally a U+003E GREATER-THAN SIGN (>) character.

      If current node is a Text or CDATASection node

      If one of the ancestors of current node is a style, script, xmp, iframe, noembed, noframes, noscript, or plaintext element, then append the value of current node's data DOM attribute literally.

      Otherwise, append the value of current node's data DOM attribute, escaped as described below.

      If current node is a Comment

      Append the literal string <!-- (U+003C LESS-THAN SIGN, U+0021 EXCLAMATION MARK, U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS), followed by the value of current node's data DOM attribute, followed by the literal string --> (U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS, U+003E GREATER-THAN SIGN).

      If current node is a ProcessingInstruction

      Append the literal string <? (U+003C LESS-THAN SIGN, U+003F QUESTION MARK), followed by the value of current node's target DOM attribute, followed by a single U+0020 SPACE character, followed by the value of current node's data DOM attribute, followed by a single U+003E GREATER-THAN SIGN character ('>').

      If current node is a DocumentType

      Append the literal string <!DOCTYPE (U+003C LESS-THAN SIGN, U+0021 EXCLAMATION MARK, U+0044 LATIN CAPITAL LETTER D, U+004F LATIN CAPITAL LETTER O, U+0043 LATIN CAPITAL LETTER C, U+0054 LATIN CAPITAL LETTER T, U+0059 LATIN CAPITAL LETTER Y, U+0050 LATIN CAPITAL LETTER P, U+0045 LATIN CAPITAL LETTER E), followed by a space (U+0020 SPACE), followed by the value of current node's name DOM attribute, followed by the literal string > (U+003E GREATER-THAN SIGN).

      Other node types (e.g. Attr) cannot occur as children of elements. If, despite this, they somehow do occur, this algorithm must raise an INVALID_STATE_ERR exception.

  3. The result of the algorithm is the string s.

Escaping a string (for the purposes of the algorithm above) consists of replacing any occurrences of the "&" character by the string "&amp;", any occurrences of the U+00A0 NO-BREAK SPACE character by the string "&nbsp;", and, if the algorithm was invoked in the attribute mode, any occurrences of the """ character by the string "&quot;", or if it was not, any occurrences of the "<" character by the string "&lt;", any occurrences of the ">" character by the string "&gt;".

Entity reference nodes are assumed to be expanded by the user agent, and are therefore not covered in the algorithm above.

It is possible that the output of this algorithm, if parsed with an HTML parser, will not return the original tree structure. For instance, if a textarea element to which a Comment node has been appended is serialized and the output is then reparsed, the comment will end up being displayed in the text field. Similarly, if, as a result of DOM manipulation, an element contains a comment that contains the literal string "-->", then when the result of serializing the element is parsed, the comment will be truncated at that point and the rest of the comment will be interpreted as markup. More examples would be making a script element contain a text node with the text string "</script>", or having a p element that contains a ul element (as the ul element's start tag would imply the end tag for the p).

8.5 Parsing HTML fragments

The following steps form the HTML fragment parsing algorithm. The algorithm optionally takes as input an Element node, referred to as the context element, which gives the context for the parser, as well as input, a string to parse, and returns a list of zero or more nodes.

Parts marked fragment case in algorithms in the parser section are parts that only occur if the parser was created for the purposes of this algorithm (and with a context element). The algorithms have been annotated with such markings for informational purposes only; such markings have no normative weight. If it is possible for a condition described as a fragment case to occur even when the parser wasn't created for the purposes of handling this algorithm, then that is an error in the specification.

  1. Create a new Document node, and mark it as being an HTML document.

  2. Create a new HTML parser, and associate it with the just created Document node.

  3. If there is a context element, run these substeps:

    1. Set the HTML parser's tokenization stage's content model flag according to the context element, as follows:

      If it is a title or textarea element
      Set the content model flag to the RCDATA state.
      If it is a style, script, xmp, iframe, noembed, or noframes element
      Set the content model flag to the CDATA state.
      If it is a noscript element
      If the scripting flag is enabled, set the content model flag to the CDATA state. Otherwise, set the content model flag to the PCDATA state.
      If it is a plaintext element
      Set the content model flag to PLAINTEXT.
      Otherwise
      Leave the content model flag in the PCDATA state.
    2. Let root be a new html element with no attributes.

    3. Append the element root to the Document node created above.

    4. Set up the parser's stack of open elements so that it contains just the single element root.

    5. Reset the parser's insertion mode appropriately.

      The parser will reference the context element as part of that algorithm.

    6. Set the parser's form element pointer to the nearest node to the context element that is a form element (going straight up the ancestor chain, and including the element itself, if it is a form element), or, if there is no such form element, to null.

  4. Place into the input stream for the HTML parser just created the input. The encoding confidence is irrelevant.

  5. Start the parser and let it run until it has consumed all the characters just inserted into the input stream.

  6. If there is a context element, return the child nodes of root, in tree order.

    Otherwise, return the children of the Document object, in tree order.

9 The XHTML syntax

This section only describes the rules for XML resources. Rules for text/html resources are discussed in the section above entitled "The HTML syntax".

9.1 Writing XHTML documents

The syntax for using HTML with XML, whether in XHTML documents or embedded in other XML documents, is defined in the XML and Namespaces in XML specifications. [XML] [XMLNS]

This specification does not define any syntax-level requirements beyond those defined for XML proper.

XML documents may contain a DOCTYPE if desired, but this is not required to conform to this specification. This specification does not define a public or system identifier, nor provide a format DTD.

According to the XML specification, XML processors are not guaranteed to process the external DTD subset referenced in the DOCTYPE. This means, for example, that using entity references for characters in XHTML documents is unsafe if they are defined in an external file (except for &lt;, &gt;, &amp;, &quot; and &apos;).

9.2 Parsing XHTML documents

This section describes the relationship between XML and the DOM, with a particular emphasis on how this interacts with HTML.

An XML parser, for the purposes of this specification, is a construct that follows the rules given in the XML specification to map a string of bytes or characters into a Document object.

An XML parser is either associated with a Document object when it is created, or creates one implicitly.

This Document must then be populated with DOM nodes that represent the tree structure of the input passed to the parser, as defined by the XML specification, the Namespaces in XML specification, and the DOM Core specification. DOM mutation events must not fire for the operations that the XML parser performs on the Document's tree, but the user agent must act as if elements and attributes were individually appended and set respectively so as to trigger rules in this specification regarding what happens when an element in inserted into a document or has its attributes set. [XML] [XMLNS] [DOMCORE] [DOMEVENTS]

Certain algorithms in this specification spoon-feed the parser characters one string at a time. In such cases, the XML parser must act as it would have if faced with a single string consisting of the concatenation of all those characters.

When an XML parser creates a script element, it must be marked as being "parser-inserted". If the parser was originally created for the XML fragment parsing algorithm, then the element must be marked as "already executed" also. When the element's end tag is parsed, the user agent must run the script element. If this causes there to be a pending external script, then the user agent must pause until that script has completed loading, and then execute it.

Since the document.write() API is not available for XML documents, much of the complexity in the HTML parser is not needed in the XML parser.

When an XML parser reaches the end of its input, it must stop parsing, following the same rules as the HTML parser.

9.3 Serializing XHTML fragments

The XML fragment serialization algorithm for a Document or Element node either returns a fragment of XML that represents that node or raises an exception.

For Documents, the algorithm must return a string in the form of a document entity, if none of the error cases below apply.

For Elements, the algorithm must return a string in the form of an internal general parsed entity, if none of the error cases below apply.

In both cases, the string returned must be XML namespace-well-formed and must be an isomorphic serialization of all of that node's child nodes, in tree order. User agents may adjust prefixes and namespace declarations in the serialization (and indeed might be forced to do so in some cases to obtain namespace-well-formed XML).

For Elements, if any of the elements in the serialization are in no namespace, the default namespace in scope for those elements must be explicitly declared as the empty string. (This doesn't apply in the Document case.) [XML] [XMLNS]

If any of the following error cases are found in the DOM subtree being serialized, then the algorithm raises an INVALID_STATE_ERR exception instead of returning a string:

These are the only ways to make a DOM unserializable. The DOM enforces all the other XML constraints; for example, trying to set an attribute with a name that contains an equals sign (=) will raised an INVALID_CHARACTER_ERR exception.

9.4 Parsing XHTML fragments

The XML fragment parsing algorithm for either returns a Document or raises a SYNTAX_ERR exception. Given a string input and an optional context element context, the algorithm is as follows:

  1. Create a new XML parser.

  2. If there is a context element, feed the parser just created the string corresponding to the start tag of that element, declaring all the namespace prefixes that are in scope on that element in the DOM, as well as declaring the default namespace (if any) that is in scope on that element in the DOM.

    A namespace prefix is in scope if the DOM Core lookupNamespaceURI() method on the element would return a non-null value for that prefix.

    The default namespace is the namespace for which the DOM Core isDefaultNamespace() method on the element would return true.

  3. Feed the parser just created the string input.

  4. If there is a context element, feed the parser just created the string corresponding to the end tag of that element.

  5. If there is an XML well-formedness or XML namespace well-formedness error, then raise a SYNTAX_ERR exception and abort these steps.

  6. If there is a context element, then return the child nodes of the root element of the resulting Document, in tree order.

    Otherwise, return the children of the Document object, in tree order.

10 Rendering

User agents are not required present HTML documents in any particular way. However, this section provides a set of suggestions for rendering HTML documents that, if followed, are likely to lead to a user experience that closely resembles the experience intended by the documents' authors. So as to avoid confusion regarding the normativity of this section, RFC2119 terms have not been used. Instead, the term "expected" is used to indicate behavior that will lead to this experience.

10.1 Introduction

In general, user agents are expected to support CSS, and many of the suggestions in this section are expressed in CSS terms. User agents that use other presentation mechanisms can derive their expected behavior by translating from the CSS rules given in this section.

In the absence of style-layer rules to the contrary (e.g. author style sheets), user agents are expected to render an element so that it conveys to the user the meaning that the element represents, as described by this specification.

The suggestions in this section generally assume a visual output medium with a resolution of 96dpi or greater, but HTML is intended to apply to multiple media (it is a media-independent language). User agents are encouraged to adapt the suggestions in this section to their target media.

10.2 The CSS user agent style sheet and presentational hints

10.2.1 Introduction

The CSS rules given in these subsections are, unless otherwise specified, expected to be used as part of the user-agent level style sheet defaults for all documents that contain HTML elements.

Some rules are intended for the author-level zero-specificity presentational hints part of the CSS cascade; these are explicitly called out as presentational hints.

Some of the rules regarding left and right margins are given here as appropriate for elements whose 'direction' property is 'ltr', and are expected to be flipped around on elements whose 'direction' property is 'rtl'. These are marked "LTR-specific".


When the text below says that an attribute attribute on an element element maps to the pixel length property (or properties) properties, it means that if element has an attribute attribute set, and parsing that attribute's value using the rules for parsing non-negative integers doesn't generate an error, then the user agent is expected to use the parsed value as a pixel length for a presentational hint for properties.

When the text below says that an attribute attribute on an element element maps to the dimension property (or properties) properties, it means that if element has an attribute attribute set, and parsing that attribute's value using the rules for parsing dimension values doesn't generate an error, then the user agent is expected to use the parsed dimension as the value for a presentational hint for properties, with the value given as a pixel length if the dimension was an integer, and with the value given as a percentage if the dimension was a percentage.

10.2.2 Display types

@namespace url(http://www.w3.org/1999/xhtml);

[hidden], area, audio:not([controls]), base, basefont, command,
datalist, head, input[type=hidden], link, menu[type=context], meta,
noembed, noframes, param, script, source, style, title {
  display: none;
}

address, article, aside, blockquote, body, center, dd, dialog, dir,
div, dl, dt, figure, footer, form, h1, h2, h3, h4, h5, h6, header, hr,
html, legend, listing, menu, nav, ol, p, plaintext, pre, rp, section,
ul, xmp { display: block; }

table { display: table; }
caption { display: table-caption; }
colgroup { display: table-column-group; }
col { display: table-column; }
thead { display: table-header-group; }
tbody { display: table-row-group; }
tfoot { display: table-footer-group; }
tr { display: table-row; }
td, th { display: table-cell; }

li { display: list-item; }

ruby { display: ruby; }
rt { display: ruby-text; }

For the purposes of the CSS table model, the col element is to be treated as if it was present as many times as its span attribute specifies.

For the purposes of the CSS table model, the colgroup element, if it contains no col element, is to be treated as if it had as many such children as its span attribute specifies.

For the purposes of the CSS table model, the colspan and rowspan attributes on td and th elements are expected to provide the special knowledge regarding cells spanning rows and columns.

For the purposes of the CSS ruby model, runs of descendants of ruby elements that are not rt or rp elements are expected to be wrapped in anonymous boxes whose 'display' property has the value 'ruby-base'.

User agents that do not support correct ruby rendering are expected to render parentheses around the text of rt elements in the absence of rp elements.

The br element is expected to render as if its contents were a single U+000A LINE FEED (LF) character and its 'white-space' property was 'pre'.

The user agent is expected to hide noscript elements for whom scripting is disabled, irrespective of CSS rules.

10.2.3 Margins and padding

@namespace url(http://www.w3.org/1999/xhtml);

article, aside, blockquote, dir, dl, figure, listing, menu, nav, ol,
p, plaintext, pre, section, ul, xmp {
  margin-top: 1em; margin-bottom: 1em;
}

dir dir, dir dl, dir menu, dir ol, dir ul,
dl dir, dl dl, dl menu, dl ol, dl ul,
menu dir, menu dl, menu menu, menu ol, menu ul,
ol dir, ol dl, ol menu, ol ol, ol ul,
ul dir, ul dl, ul menu, ul ol, ul ul {
  margin-top: 0; margin-bottom: 0;
}

h1 { margin-top: 0.67em; margin-bottom; 0.67em; }
h2 { margin-top: 0.83em; margin-bottom; 0.83em; }
h3 { margin-top: 1.00em; margin-bottom; 1.00em; }
h4 { margin-top: 1.33em; margin-bottom; 1.33em; }
h5 { margin-top: 1.67em; margin-bottom; 1.67em; }
h6 { margin-top: 2.33em; margin-bottom; 2.33em; }

dd { margin-left: 40px; } /* LTR-specific: use 'margin-right' for rtl elements */
dir, menu, ol, ul { padding-left: 40px; } /* LTR-specific: use 'padding-right' for rtl elements */
blockquote, figure { margin-left: 40px; margin-right: 40px; }

table { border-spacing: 2px; border-collapse: separate; }
td, th { padding: 1px; }

For each property in the table below, given a body element, the first attribute that exists maps to the pixel length property on the body element. If none of the attributes for a property are found, or if the value of the attribute that was found cannot be parsed successfully, then a default value of 8px is expected to be used for that property instead.

Property Source
'margin-top' body element's marginheight attribute
The body element's container frame element's marginheight attribute
body element's topmargin attribute
'margin-right' body element's marginwidth attribute
The body element's container frame element's marginwidth attribute
body element's rightmargin attribute
'margin-bottom' body element's marginheight attribute
The body element's container frame element's marginheight attribute
body element's topmargin attribute
'margin-left' body element's marginwidth attribute
The body element's container frame element's marginwidth attribute
body element's rightmargin attribute

If the body element's Document's browsing context is a nested browsing context, and the browsing context container of that nested browsing context is a frame or iframe element, then the the container frame element of the body element is that frame or iframe element. Otherwise, there is no container frame element.


If the Document has a root element, and the Document's browsing context is a nested browsing context, and the browsing context container of that nested browsing context is a frame or iframe element, and that element has a scrolling attribute, then the user agent is expected to compare the value of the attribute in an ASCII case-insensitive manner to the values in the first column of the following table, and if one of them matches, then the user agent is expected to treat that attribute as a presentational hint for the aforementioned root element's 'overflow' property, setting it to the value given in the corresponding cell on the same row in the second column:

Attribute value 'overflow' value
on 'scroll'
scroll 'scroll'
yes 'scroll'
off 'hidden'
noscroll 'hidden'
no 'hidden'
auto 'auto'

The table element's cellspacing attribute maps to the pixel length property 'border-spacing' on the element.

The table element's cellpadding attribute maps to the pixel length properties 'padding-top', 'padding-right', 'padding-bottom', and 'padding-left' of any td and th elements that have corresponding cells in the table corresponding to the table element.

The table element's hspace attribute maps to the dimension properties 'margin-left' and 'margin-right' on the table element.

The table element's vspace attribute maps to the dimension properties 'margin-top' and 'margin-bottom' on the table element.

The table element's height attribute maps to the dimension property 'height' on the table element.

The table element's width attribute maps to the dimension property 'width' on the table element.

The col element's width attribute maps to the dimension property 'width' on the col element.

The tr element's height attribute maps to the dimension property 'height' on the tr element.

The td and th elements' height attributes map to the dimension property 'height' on the element.

The td and th elements' width attributes map to the dimension property 'width' on the element.


In quirks mode, the following rules are also expected to apply:

@namespace url(http://www.w3.org/1999/xhtml);

form { margin-bottom: 1em; }

When a Document is in quirks mode, margins on HTML elements that collapse with the top or bottom of the initial containing block, or the top of bottom of td or th elements, are expected to be collapsed to zero.

10.2.4 Alignment

@namespace url(http://www.w3.org/1999/xhtml);

thead, tbody, tfoot, table > tr { vertical-align: middle; }
tr, td, th { vertical-align: inherit; }
sub { vertical-align: sub; }
sup { vertical-align: super; }
th { text-align: center; }

The following rules are also expected to apply, as presentational hints:

@namespace url(http://www.w3.org/1999/xhtml);

table[align=left] { float: left; }
table[align=right] { float: right; }
table[align=center], table[align=abscenter],
table[align=abdmiddle], table[align=middle] {
  margin-left: auto; margin-right: auto;
}

caption[align=bottom] { caption-side: bottom; }
p[align=left], h1[align=left], h2[align=left], h3[align=left],
h4[align=left], h5[align=left], h6[align=left] {
  text-align: left;
}
p[align=right], h1[align=right], h2[align=right], h3[align=right],
h4[align=right], h5[align=right], h6[align=right] {
  text-align: right;
}
p[align=center], h1[align=center], h2[align=center], h3[align=center],
h4[align=center], h5[align=center], h6[align=center] {
  text-align: center;
}
p[align=justify], h1[align=justify], h2[align=justify], h3[align=justify],
h4[align=justify], h5[align=justify], h6[align=justify] {
  text-align: justify;
}
col[valign=top], thead[valign=top], tbody[valign=top],
tfoot[valign=top], tr[valign=top], td[valign=top], th[valign=top] {
  vertial-align: top;
}
col[valign=middle], thead[valign=middle], tbody[valign=middle],
tfoot[valign=middle], tr[valign=middle], td[valign=middle], th[valign=middle] {
  vertial-align: middle;
}
col[valign=bottom], thead[valign=bottom], tbody[valign=bottom],
tfoot[valign=bottom], tr[valign=bottom], td[valign=bottom], th[valign=bottom] {
  vertial-align: bottom;
}
col[valign=baseline], thead[valign=baseline], tbody[valign=baseline],
tfoot[valign=baseline], tr[valign=baseline], td[valign=baseline], th[valign=baseline] {
  vertial-align: baseline;
}

The center element, the caption element unless specified otherwise below, and the div element when its align attribute's value is an ASCII case-insensitive match for the string "center", are expected to center text within themselves, as if they had their 'text-align' property set to 'center' in a presentational hint, and to align descendants to the center.

The div, caption, thead, tbody, tfoot, tr, td, and th elements, when they have an align attribute whose value is an ASCII case-insensitive match for the string "left", are expected to left-align text within themselves, as if they had their 'text-align' property set to 'left' in a presentational hint, and to align descendants to the left.

The div, caption, thead, tbody, tfoot, tr, td, and th elements, when they have an align attribute whose value is an ASCII case-insensitive match for the string "right", are expected to right-align text within themselves, as if they had their 'text-align' property set to 'right' in a presentational hint, and to align descendants to the right.

The div, caption, thead, tbody, tfoot, tr, td, and th elements, when they have an align attribute whose value is an ASCII case-insensitive match for the string "justify", are expected to full-justify text within themselves, as if they had their 'text-align' property set to 'justify' in a presentational hint, and to align descendants to the left.

When a user agent is to align descendants of a node, the user agent is expected to align only those descendants that have both their 'margin-left' and 'margin-right' properties computing to a value other than 'auto', that are over-constrained and that have one of those two margins with a used value forced to a greater value, and that do not themselves have an applicable align attribute.

10.2.5 Fonts and colors


The initial value for the 'color' property is expected to be black. The initial value for the 'background-color' property is expected to be 'transparent'. The canvas's background is expected to be white.


The article, aside, nav, and section elements are expected to affect the styling of h1 elements, based on the nesting depth. If x is a selector that matches elements that are either article, aside, nav, or section elements, then the following rules capture what is expected:

@namespace url(http://www.w3.org/1999/xhtml);

x h1 { font-size: 1.50em; }
x x h1 { font-size: 1.17em; }
x x x h1 { font-size: 1.00em; }
x x x x h1 { font-size: 0.83em; }
x x x x x h1 { font-size: 0.67em; }

When a body, table, thead, tbody, tfoot, tr, td, or th element has a background attribute set to a non-empty value, the new value is expected to be resolved relative to the element, and if this is successful, the user agent is expected to treat the attribute as a presentational hint setting the element's 'background-image' property to the resulting absolute URL.

When a body, table, thead, tbody, tfoot, tr, td, or th element has a bgcolor attribute set, the new value is expected to be parsed using the rules for parsing a legacy color value, and the user agent is expected to treat the attribute as a presentational hint setting the element's 'background-color' property to the resulting color.

When a body element has a text attribute, its value is expected to be parsed using the rules for parsing a legacy color value, and the user agent is expected to treat the attribute as a presentational hint setting the element's 'color' property to the resulting color.

When a body element has a link attribute, its value is expected to be parsed using the rules for parsing a legacy color value, and the user agent is expected to treat the attribute as a presentational hint setting the 'color' property of any element in the Document matching the ':link' pseudo-class to the resulting color.

When a body element has a vlink attribute, its value is expected to be parsed using the rules for parsing a legacy color value, and the user agent is expected to treat the attribute as a presentational hint setting the 'color' property of any element in the Document matching the ':visited' pseudo-class to the resulting color.

When a body element has a alink attribute, its value is expected to be parsed using the rules for parsing a legacy color value, and the user agent is expected to treat the attribute as a presentational hint setting the 'color' property of any element in the Document matching the ':active' pseudo-class and either the ':link' pseudo-class or the ':visited' pseudo-class to the resulting color.

When a table element has a bordercolor attribute, its value is expected to be parsed using the rules for parsing a legacy color value, and the user agent is expected to treat the attribute as a presentational hint setting the element's 'border-top-color', 'border-right-color', 'border-bottom-color', and 'border-right-color' properties to the resulting color.


When a font element has a color attribute, its value is expected to be parsed using the rules for parsing a legacy color value, and the user agent is expected to treat the attribute as a presentational hint setting the element's 'color' property to the resulting color.

When a font element has a face attribute, the user agent is expected to treat the attribute as a presentational hint setting the element's 'font-family' property to the attribute's value.

When a font element has a pointsize attribute, the user agent is expected to parse that attribute's value using the rules for parsing non-negative integers, and if this doesn't generate an error, then the user agent is expected to use the parsed value as a point length for a presentational hint for the 'font-size' property on the element.

When a font element has a size attribute, the user agent is expected to use the following steps to treat the attribute as a presentational hint setting the element's 'font-size' property:

  1. Let input be the attribute's value.

  2. Let position be a pointer into input, initially pointing at the start of the string.

  3. Skip whitespace.

  4. If position is past the end of input, there is no presentational hint. Abort these steps.

  5. If the character at position is a U+002B PLUS SIGN character (+), then let mode be relative-plus, and advance position to the next character. Otherwise, if the character at position is a U+002D HYPHEN-MINUS character (-), then let mode be relative-minus, and advance position to the next character. Otherwise, let mode be absolute.

  6. Collect a sequence of characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), and let the resulting sequence be digits.

  7. If digits is the empty string, there is no presentational hint. Abort these steps.

  8. Interpret digits as a base-ten integer. Let size be the resulting number.

  9. If mode is is relative-plus, then increment value by 3. If mode is is relative-minus, then decrement value by 3.

  10. If value is greater than 7, let it be 7.

  11. If value is less than 1, let it be 1.

  12. Set 'font-size' to the keyword corresponding to the value of value according to the following table:

    value 'font-size' keyword Notes
    1 xx-small
    2 small
    3 medium
    4 large
    5 x-large
    6 xx-large
    7 xxx-large see below

    The 'xxx-large' value is a non-CSS value used here to indicate a font size one "step" larger than 'xx-large'.

10.3 Replaced elements

10.3.1 Embedded content

The applet, canvas, embed, iframe, and video elements are expected to be treated as replaced elements.

An object element that represents an image, plugin, or nested browsing context is expected to be treated as a replaced element. Other object elements are expected to be treated as ordinary elements in the rendering model.

The audio element, when it has a controls attribute, is expected to be treated as a replaced element about one line high, as wide as is necessary to expose the user agent's user interface features.

The video element's controls attribute is not expected to affect the size of the rendering; controls are expected to be overlaid with the page content without causing any layout changes, and are expected to disappear when the user does not need them.

Resizing video and canvas elements does not interrupt video playback or clear the canvas.


The following CSS rules are expected to apply:

@namespace url(http://www.w3.org/1999/xhtml);

iframe { border: 2px inset; }

10.3.2 Images

When an img element or an input element when its type attribute is in the Image Button state represents an image, it is expected to be treated as a replaced element.

When an img element or an input element when its type attribute is in the Image Button state does not represent an image, but the element already has instrinsic dimensions (e.g. from the dimension attributes or CSS rules), and either the user agent has reason to believe that the image will become available and be rendered in due course or the Document is in quirks mode, the element is expected to be treated as a replaced element whose content is the text that the element represents, if any, optionally alongside an icon indicating that the image is being obtained. For input elements, the text is expected to appear button-like to indicate that the element is a button.

When an img element represents some text and the user agent does not expect this to change, the element is expected to be treated as an inline element whose content is the text, optionally with an icon indicating that an image is missing.

When an img element represents nothing and the user agent does not expect this to change, the element is expected to not be rendered at all.

When an img element might be a key part of the content, but neither the image nor any kind of alternative text is available, and the user agent does not expect this to change, the element is expected to be treated as an inline element whose content is an icon indicating that an image is missing.

When an input element whose type attribute is in the Image Button state does not represent an image and the user agent does not expect this to change, the element is expected to be treated as a replaced element consisting of a button whose content is the element's alternative text. The intrinsic dimensions of the button are expected to be about one line in height and whatever width is necessary to render the text on one line.

The icons mentioned above are expected to be relatively small so as not to disrupt most text but be easily clickable. In a visual environment, for instance, icons could be 16 pixels by 16 pixels square, or 1em by 1em if the images are scalable. In an audio environment, the icon could be a short bleep. The icons are intended to indicate to the user that they can be used to get to whatever options the UA provides for images, and, where appropriate, are expected to provide access to the context menu that would have come up if the user interacted with the actual image.


The following CSS rules are expected to apply when the Document is in quirks mode:

@namespace url(http://www.w3.org/1999/xhtml);

img[align=left] { margin-right: 3px; }
img[align=right] { margin-left: 3px; }

10.3.3 Attributes for embedded content and images

The following CSS rules are expected to apply as presentational hints:

@namespace url(http://www.w3.org/1999/xhtml);

iframe[frameborder=0], iframe[frameborder=no] { border: none; }

applet[align=left], embed[align=left], iframe[align=left],
img[align=left], input[type=image][align=left], object[align=left] {
  float: left;
}

applet[align=right], embed[align=right], iframe[align=right],
img[align=right], input[type=image][align=right], object[align=right] {
  float: right;
}

applet[align=top], embed[align=top], iframe[align=top],
img[align=top], input[type=image][align=top], object[align=top] {
  vertical-align: top;
}

applet[align=bottom], embed[align=bottom], iframe[align=bottom],
img[align=bottom], input[type=image][align=bottom], object[align=bottom],
applet[align=baseline], embed[align=baseline], iframe[align=baseline],
img[align=baseline], input[type=image][align=baseline], object[align=baseline] {
  vertical-align: baseline;
}

applet[align=texttop], embed[align=texttop], iframe[align=texttop],
img[align=texttop], input[type=image][align=texttop], object[align=texttop] {
  vertical-align: text-top;
}

applet[align=absmiddle], embed[align=absmiddle], iframe[align=absmiddle],
img[align=absmiddle], input[type=image][align=absmiddle], object[align=absmiddle],
applet[align=abscenter], embed[align=abscenter], iframe[align=abscenter],
img[align=abscenter], input[type=image][align=abscenter], object[align=abscenter] {
  vertical-align: middle;
}

applet[align=bottom], embed[align=bottom], iframe[align=bottom],
img[align=bottom], input[type=image][align=bottom],
object[align=bottom] {
  vertical-align: bottom;
}

When an applet, embed, iframe, img, or object element, or an input element whose type attribute is in the Image Button state, has an align attribute whose value is an ASCII case-insensitive match for the string "center" or the string "middle", the user agent is expected to act as if the element's 'vertical-align' property was set to a value that aligns the vertical middle of the element with the parent element's baseline.

The hspace attribute of applet, embed, iframe, img, or object elements, and input elements with a type attribute in the Image Button state, maps to the dimension properties 'margin-left' and 'margin-right' on the element.

The vspace attribute of applet, embed, iframe, img, or object elements, and input elements with a type attribute in the Image Button state, maps to the dimension properties 'margin-top' and 'margin-bottom' on the element.

When an img element, object element, or input element with a type attribute in the Image Button state is contained within a hyperlink and has a border attribute whose value, when parsed using the rules for parsing non-negative integers, is found to be a number greater than zero, the user agent is expected to use the parsed value for eight presentational hints: four setting the parsed value as a pixel length for the element's 'border-top-width', 'border-right-width', 'border-bottom-width', and 'border-left-width' properties, and four setting the element's 'border-top-style', 'border-right-style', 'border-bottom-style', and 'border-left-style' properties to the value 'solid'.

The width and height attributes on applet, embed, iframe, img, object or video elements, and input elements with a type attribute in the Image Button state, map to the dimension properties 'width' and 'height' on the element respectively.

10.3.4 Image maps

Shapes on an image map are expected to act, for the purpose of the CSS cascade, as elements independent of the original area element that happen to match the same style rules but inherit from the img or object element.

For the purposes of the rendering, only the 'cursor' property is expected to have any effect on the shape.

Thus, for example, if an area element has a style attribute that sets the 'cursor' property to 'help', then when the user designates that shape, the cursor would change to a Help cursor.

Similarly, if an area element had a CSS rule that set its 'cursor' property to 'inherit' (or if no rule setting the 'cursor' property matched the element at all), the shape's cursor would be inherited from the img or object element of the image map, not from the parent of the area element.

10.3.5 Tool bars

When a menu element's type attribute is in the tool bar state, the element is expected to be treated as a replaced element with a height about two lines high and a width derived from the contents of the element.

The element is expected to have, by default, the appearance of a tool bar on the user agent's platform. It is expected to contain the menu that is built from the element.

...example with screenshot...

10.4 Bindings

10.4.1 Introduction

A number of elements have their rendering defined in terms of the 'binding' property. [BECSS]

The CSS snippets below set the 'binding' property to a user-agent-defined value, represented below by keywords like bb. The rules then described for these bindings are only expected to apply if the element's 'binding' property has not been overriden (e.g. by the author) to have another value.

Exactly how the bindings are implemented is not specified by this specification. User agents are encouraged to make their bindings set the 'appearance' CSS property appropriately to achieve platform-native appearances for widgets, and are expected to implement any relevant animations, etc, that are appropriate for the platform. [CSSUI]


The converting a character width to pixels algorithm, used by some of the bindings below, returns (size-1avg + max, where size is the character width to convert, avg is the average character width of the primary font for the element for which the algorithm is being run, in pixels, and max is the maximum character width of that same font, also in pixels. (The element's 'letter-spacing' property does not affect the result.)

10.4.2 The bb element

@namespace url(http://www.w3.org/1999/xhtml);

bb:empty { binding: bb; }

When the bb binding applies to a bb element, the element is expected to render as an 'inline-block' box rendered as a button, about one line high, containing text derived from the element's type attribute in a user-agent-defined (and probably locale-specific) fashion.

10.4.3 The button element

@namespace url(http://www.w3.org/1999/xhtml);

button { binding: button; }

When the button binding applies to a button element, the element is expected to render as an 'inline-block' box rendered as a button whose contents are the contents of the element.

10.4.4 The datagrid element

This section will probably include details on how to render DATAGRID (including its pseudo-elements), drag-and-drop, etc, in a visual medium, in concert with CSS. Implementation experience is desired before this section is filled in.

10.4.5 The details element

@namespace url(http://www.w3.org/1999/xhtml);

details { binding: details; }

When the details binding applies to a details element, the element is expected to render as a 'block' box with its 'padding-left' property set to '40px'. The element's shadow tree is expected to take a child element that matches the selector :bound-element > legend:first-child and place it in a first 'block' box container, and then take the remaining child nodes and place them in a later 'block' box container.

The first container is expected to contain at least one line box, and that line box is expected to contain a triangle widget, horizontally positioned within the left padding of the details element. That widget is expected to allow the user to request that the details be shown or hidden.

The later container is expected to have its 'overflow' property set to 'hidden'. When the details element has an open attribute, the later container is expected to have its 'height' set to 'auto'; when it does not, the later container is expected to have its 'height' set to 0.

10.4.6 The input element as a text entry widget

@namespace url(http://www.w3.org/1999/xhtml);

input { binding: input-textfield; }
input[type=password] { binding: input-password; }
/* later rules override this for other values of type="" */

When the input-textfield binding applies to an input element whose type attribute is in the Text, Search, URL, or E-mail state, the element is expected to render as an 'inline-block' box rendered as a text field.

When the input-password binding applies, to an input element whose type attribute is in the Password state, the element is expected to render as an 'inline-block' box rendered as a text field whose contents are obscured.

If an input element whose type attribute is in one of the above states has a size attribute, and parsing that attribute's value using the rules for parsing non-negative integers doesn't generate an error, then the user agent is expected to use the attribute as a presentational hint for the 'width' property on the element, with the value obtained from applying the converting a character width to pixels algorithm to the value of the attribute.

If an input element whose type attribute is in one of the above states does not have a size attribute, then the user agent is expected to act as if it had a user-agent-level style sheet rule setting the 'width' property on the element to the value obtained from applying the converting a character width to pixels algorithm to the number 20.

10.4.7 The input element as domain-specific widgets

@namespace url(http://www.w3.org/1999/xhtml);

input[type=datetime] { binding: input-datetime; }
input[type=date] { binding: input-date; }
input[type=month] { binding: input-month; }
input[type=week] { binding: input-week; }
input[type=time] { binding: input-time; }
input[type=datetime-local] { binding: input-datetime-local; }
input[type=number] { binding: input-number; }

When the input-datetime binding applies to an input element whose type attribute is in the Date and Time state, the element is expected to render as an 'inline-block' box depicting a Date and Time control.

When the input-date binding applies to an input element whose type attribute is in the Date state, the element is expected to render as an 'inline-block' box depicting a Date control.

When the input-month binding applies to an input element whose type attribute is in the Month state, the element is expected to render as an 'inline-block' box depicting a Month control.

When the input-week binding applies to an input element whose type attribute is in the Week state, the element is expected to render as an 'inline-block' box depicting a Week control.

When the input-time binding applies to an input element whose type attribute is in the Time state, the element is expected to render as an 'inline-block' box depicting a Time control.

When the input-datetime-local binding applies to an input element whose type attribute is in the Local Date and Time state, the element is expected to render as an 'inline-block' box depicting a Local Date and Time control.

When the input-number binding applies to an input element whose type attribute is in the Number state, the element is expected to render as an 'inline-block' box depicting a Number control.

These controls are all expected to be about one line high, and about as wide as necessary to show the widest possible value.

10.4.8 The input element as a range control

@namespace url(http://www.w3.org/1999/xhtml);

input[type=range] { binding: input-range; }

When the input-range binding applies to an input element whose type attribute is in the Range state, the element is expected to render as an 'inline-block' box depicting a slider control.

When the control is wider than it is tall (or square), the control is expected to be a horizontal slider, with the lowest value on the right if the 'direction' property on this element has a computed value of 'rtl', and on the left otherwise. When the control is taller than it is wide, it is expected to be a vertical slider, with the lowest value on the bottom.

Predefined suggested values (provided by the list attribute) are expected to be shown as tick marks on the slider, which the slider can snap to.

10.4.9 The input element as a color well

@namespace url(http://www.w3.org/1999/xhtml);

input[type=color] { binding: input-color; }

When the input-color binding applies to an input element whose type attribute is in the Color state, the element is expected to render as an 'inline-block' box depicting a color well, which, when activated, provides the user with a color picker (e.g. a color wheel or color palette) from which the color can be changed.

Predefined suggested values (provided by the list attribute) are expected to be shown in the color picker interface, not on the color well itself.

10.4.10 The input element as a check box and radio button widgets

@namespace url(http://www.w3.org/1999/xhtml);

input[type=checkbox] { binding: input-checkbox; }
input[type=radio] { binding: input-radio; }

When the input-checkbox binding applies to an input element whose type attribute is in the Checkbox state, the element is expected to render as an 'inline-block' box containing a single check box control, with no label.

When the input-radio binding applies to an input element whose type attribute is in the Radio Button state, the element is expected to render as an 'inline-block' box containing a single radio button control, with no label.

10.4.11 The input element as a file upload control

@namespace url(http://www.w3.org/1999/xhtml);

input[type=file] { binding: input-file; }

When the input-file binding applies to an input element whose type attribute is in the File Upload state, the element is expected to render as an 'inline-block' box containing a span of text giving the filename(s) of the selected files, if any, followed by a button that, when activated, provides the user with a file picker from which the selection can be changed.

10.4.12 The input element as a button

@namespace url(http://www.w3.org/1999/xhtml);

input[type=submit], input[type=reset], input[type=button] {
  binding: input-button;
}

When the input-button binding applies to an input element whose type attribute is in the Submit Button, Reset Button, or Button state, the element is expected to render as an 'inline-block' box rendered as a button, about one line high, containing the contents of the element's value attribute, if any, or text derived from the element's type attribute in a user-agent-defined (and probably locale-specific) fashion, if not.

10.4.13 The marquee element

...(Waiting til I've specced the DOM side of this)...

10.4.14 The meter element

@namespace url(http://www.w3.org/1999/xhtml);

meter {
  binding: meter;
}

When the meter binding applies to a meter element, the element is expected to render as an 'inline-block' box with a 'height' of '1em' and a 'width' of '5em', a 'vertical-align' of '-0.2em', and with its contents depicting a gauge.

When the element is wider than it is tall (or square), the depiction is expected to be of a horizontal gauge, with the minimum value on the right if the 'direction' property on this element has a computed value of 'rtl', and on the left otherwise. When the element is taller than it is wide, it is expected to depict a vertical gauge, with the minimum value on the bottom.

User agents are expected to use a presentation consistent with platform conventions for gauges, if any.

Requirements for what must be depicted in the gauge are included in the definition of the meter element.

10.4.15 The progress element

@namespace url(http://www.w3.org/1999/xhtml);

progress {
  binding: progress;
}

When the progress binding applies to a progress element, the element is expected to render as an 'inline-block' box with a 'height' of '1em' and a 'width' of '10em', a 'vertical-align' of '-0.2em', and with its contents depicting a horizontal progress bar, with the start on the right and the end on the left if the 'direction' property on this element has a computed value of 'rtl', and with the start on the left and the end on the right otherwise.

User agents are expected to use a presentation consistent with platform conventions for progress bars. In particular, user agents are expected to use different presentations for determinate and indeterminate progress bars. User agents are also expected to vary the presentation based on the dimensions of the element.

For example, on some platforms for showing indeterminate progress there is an asychronous progress indicator with square dimensions, which could be used when the element is square, and an indeterminate progress bar, which could be used when the element is wide.

Requirements for how to determine if the progress bar is determinate or indeterminate, and what progress a determinate progress bar is to show, are included in the definition of the progress element.

10.4.16 The select element

@namespace url(http://www.w3.org/1999/xhtml);

select {
  binding: select;
}

When the select binding applies to a select element whose multiple attribute is present, the element is expected to render as a multi-select list box.

When the select binding applies to a select element whose multiple attribute is absent, and the element's size attribute specifies a value greater than 1, the element is expected to render as a single-select list box.

When the element renders as a list box, it is expected to render as an 'inline-block' box whose 'height' is the height necessary to contain as many rows for items as specified by the element's size attribute, or four rows if the attribute is absent, and whose 'width' is the width of the select's labels plus the width of a scrollbar.

When the select binding applies to a select element whose multiple attribute is absent, and the element's size attribute is either absent or specifies either no value (an error), or a value less than or equal to 1, the element is expected to render as a one-line drop down box whose width is the width of the select's labels.

In either case (list box or drop-down box), the element's items are expected to be the element's list of options, with the element's optgroup element children providing headers for groups of options where applicable.

The width of the select's labels is the wider of the width necessary to render the widest optgroup, and the width necessary to render the widest option element in the element's list of options (including its indent, if any).

An optgroup element is expected to be rendered by displaying the element's label attribute.

An option element is expected to be rendered by displaying the element's label, indented under its optgroup element if it has one.

10.4.17 The textarea element

@namespace url(http://www.w3.org/1999/xhtml);

textarea { binding: textarea; }

When the textarea binding applies to a textarea element, the element is expected to render as an 'inline-block' box rendered as a multiline text field.

If the element has a cols attribute, and parsing that attribute's value using the rules for parsing non-negative integers doesn't generate an error, then the user agent is expected to use the attribute as a presentational hint for the 'width' property on the element, with the value obtained from applying the converting a character width to pixels algorithm to the value of the attribute and then adding the width of a scroll bar.

If the element has a rows attribute, and parsing that attribute's value using the rules for parsing non-negative integers doesn't generate an error, then the user agent is expected to use the attribute as a presentational hint for the 'height' property on the element, with the value being the specified number of lines, plus the height of a scrollbar.

10.5 Frames and framesets

When an html element's second child element is a frameset element, the user agent is expected to render the frameset element as described below across the surface of the view, instead of applying the usual CSS rendering rules.

When rendering a frameset on a surface, the user agent is expected to use the following layout algorithm:

  1. The cols and rows variables are lists of zero or more pairs consisting of a number and a unit, the unit being one of percentage, relative, and absolute.

    Use the rules for parsing a list of dimensions to parse the value of the element's cols attribute, if there is one. Let cols be the result, or an empty list if there is no such attribute.

    Use the rules for parsing a list of dimensions to parse the value of the element's rows attribute, if there is one. Let rows be the result, or an empty list if there is no such attribute.

  2. For any of the entries in cols or rows that have the number zero and the unit relative, change the entry's number to one.

  3. If cols has no entries, then add a single entry consisting of the value 1 and the unit relative to cols.

    If rows has no entries, then add a single entry consisting of the value 1 and the unit relative to rows.

  4. Invoke the algorithm defined below to convert a list of dimensions to a list of pixel values using cols as the input list, and the width of the surface that the frameset is being rendered into, in CSS pixels, as the input dimension. Let sized cols be the resulting list.

    Invoke the algorithm defined below to convert a list of dimensions to a list of pixel values using rows as the input list, and the height of the surface that the frameset is being rendered into, in CSS pixels, as the input dimension. Let sized rows be the resulting list.

  5. Split the surface into a grid of w×h rectangles, where w is the number of entries in sized cols and h is the number of entries in sized rows.

    Size the columns so that each column in the grid is as many CSS pixels wide as the corresponding entry in the sized cols list.

    Size the rows so that each row in the grid is as many CSS pixels high as the corresponding entry in the sized rows list.

  6. Let children be the list of frame and frameset elements that are children of the frameset element for which the algorithm was invoked.

  7. For each row of the grid of rectangles created in the previous step, from top to bottom, run these substeps:

    1. For each rectangle in the row, from left to right, run these substeps:

      1. If there are any elements left in children, take the first element in the list, and assign it to the rectangle.

        If this is a frameset element, then recurse the entire frameset layout algorithm for that frameset element, with the rectangle as the surface.

        Otherwise, it is a frame element; create a nested browsing context sized to fit the rectangle.

      2. If there are any elements left in children, remove the first element from children.

  8. If the frameset element has a border, draw an outer set of borders around the rectangles, using the element's frame border color.

    For each rectangle, if there is an element assigned to that rectangle, and that element has a border, draw an inner set of borders around that rectangle, using the element's frame border color.

    For each (visible) border that does not abut a rectangle that is assigned a frame element with a noresize attribute (including rectangles in further nested frameset elements), the user agent is expected to allow the user to move the border, resizing the rectangles within, keeping the proportions of any nested frameset grids.

    A frameset or frame element has a border if the following algorithm returns true:

    1. If the element has a frameborder attribute whose value is not the empty string and whose first character is either a U+0031 DIGIT ONE (1), a U+0079 LATIN SMALL LETTER Y, or a U+0059 LATIN CAPITAL LETTER Y, then return true.

    2. Otherwise, if the element has a frameborder attribute, return false.

    3. Otherwise, if the element has a parent element that is a frameset element, then return true if that element has a border, and false if it does not.

    4. Otherwise, return true.

    The frame border color of a frameset or frame element is the color obtained from the following algorithm:

    1. If the element has a bordercolor attribute, then return the color obtained from applying the rules for parsing a legacy color value to that attribute's value.

    2. Otherwise, if the element has a parent element that is a frameset element, then the frame border color of that element.

    3. Otherwise, return gray.

The algorithm to convert a list of dimensions to a list of pixel values consists of the following steps:

  1. Let input list be the list of numbers and units passed to the algorithm.

    Let output list be a list of numbers the same length as input list, all zero.

    Entries in output list correspond to the entries in input list that have the same position.

  2. Let input dimension be the size passed to the algorithm.

  3. Let count percentage be the number of entries in input list whose unit is percentage.

    Let total percentage be the sum of all the numbers in input list whose unit is percentage.

    Let count relative be the number of entries in input list whose unit is relative.

    Let total relative be the sum of all the numbers in input list whose unit is relative.

    Let count absolute be the number of entries in input list whose unit is absolute.

    Let total absolute be the sum of all the numbers in input list whose unit is absolute.

    Let remaining space be the value of input dimension.

  4. If total absolute is greater than remaining space, then for each entry in input list whose unit is absolute, set the corresponding value in output list to the number of the entry in input list multiplied by remaining space and divided by total absolute. Then, set remaining space to zero.

    Otherwise, for each entry in input list whose unit is absolute, set the corresponding value in output list to the number of the entry in input list. Then, decrement remaining space by total absolute.

  5. If total percentage multiplied by the input dimension and divided by 100 is greater than remaining space, then for each entry in input list whose unit is percentage, set the corresponding value in output list to the number of the entry in input list multiplied by remaining space and divided by total percentage. Then, set remaining space to zero.

    Otherwise, for each entry in input list whose unit is percentage, set the corresponding value in output list to the number of the entry in input list multiplied by the input dimension and divided by 100. Then, decrement remaining space by total percentage multiplied by the input dimension and divided by 100.

  6. For each entry in input list whose unit is relative, set the corresponding value in output list to the number of the entry in input list multiplied by remaining space and divided by total relative.

  7. Return output list.

User agents working with integer values for frame widths (as opposed to user agents that can lay frames out with subpixel accuracy) are expected to distribute the remainder first the last entry whose unit is relative, then equally (not proportionally) to each entry whose unit is percentage, then equally (not proportionally) to each entry whose unit is absolute, and finally, failing all else, to the last entry.

10.6 Interactive media

10.6.1 Links, forms, and navigation

User agents are expected to allow the user to control aspects of hyperlink activation and form submission, such as which browsing context is to be used for the subsequent navigation.

User agents are expected to allow users to discover the destination of hyperlinks and of forms before triggering their navigation.

User agents are expected to inform the user of whether a hyperlink includes hyperlink auditing, and to let them know at a minimum which domains will be contacted as part of such auditing.

User agents are expected to allow users to navigate browsing contexts to the resources indicated by the cite attributes on q, blockquote, ins, and del elements.

User agents are expected to surface hyperlinks created by link elements in their user interface.

While link elements that create hyperlinks will match the ':link' or ':visited' pseudo-classes, will react to clicks if visible, and so forth, this does not extend to any browser interface constructs that expose those same links. Activating a link through the browser's interface, rather than in the page itself, does not trigger click events and the like.

10.6.2 The mark element

User agents are expected to allow the user to cycle through all the mark elements in a Document. User agents are also expected to bring their existence to the user's attention, even when they are off-screen, e.g. by highlighting portions of the scroll bar that represent portions of the document that contain mark elements.

10.6.3 The title attribute

Given an element (e.g. the element designated by the mouse cursor), if the element, or one of its ancestors, has a title attribute, and the nearest such attribute has a value that is not the empty string, it is expected that the user agent will expose the contents of that attribute as a tooltip.

U+000A LINE FEED (LF) characters are expected to cause line breaks in the tooltip.

User agents are expected to allow the user to request the opportunity to obtain a physical form (or a representation of a physical form) of a Document. For example, selecting the option to print a page or convert it to PDF format.

When the user actually obtains a physical form (or a representation of a physical form) of a Document, the user agent is expected to create a new view with the print media, render the result, and the discard the view.

10.8 Interaction with CSS

Must define that in CSS, tag and attribute names in HTML documents, and class names in quirks mode documents, are case-insensitive, as well as saying which attribute values must be compared case-insensitively.

11 Obsolete features

Authors and documents must not use the features listed in this section. They are documented to enable user agents to support legacy content in an interoperable fashion.

11.1 Self-contained features

11.1.1 The applet element

The applet element is a Java-specific variant of the embed element. In HTML5 the applet element is obsoleted so that all extension frameworks (Java, .NET, Flash, etc) are handled in a consistent manner.

If the sandboxed plugins browsing context flag is set on the browsing context for which the applet element's document is the active document, then the element must be ignored (it represents nothing).

Otherwise, define how the element works, if supported.

[XXX] interface HTMLDocument {
  readonly attribute HTMLCollection applets;
};

The applets attribute must return an HTMLCollection rooted at the Document node, whose filter matches only applet elements.

11.1.2 The marquee element

...

11.2 Other elements and attributes

The following elements are obsolete and either have no meaning whatsoever or have no requirements beyond those described elsewhere in this specification:


The following attributes are obsolete and either have no meaning whatsoever or have no requirements beyond those described elsewhere in this specification:

11.3 Other DOM APIs

These APIs expose obsolete content attributes.

The [XXX] below is for some annotation meaning "this is just another part of the named interface, and should be treated as if it had been part of the main interface definition".

[XXX] interface HTMLBodyElement {
           attribute DOMString text;
           attribute DOMString bgColor;
           attribute DOMString background;
           attribute DOMString link;
           attribute DOMString vLink;
           attribute DOMString aLink;
};

The text DOM attribute of the body element must reflect the element's text content attribute.

The bgColor DOM attribute of the body element must reflect the element's bgcolor content attribute.

The background DOM attribute of the body element must reflect the element's background content attribute.

The link DOM attribute of the body element must reflect the element's link content attribute.

The aLink DOM attribute of the body element must reflect the element's alink content attribute.

The vLink DOM attribute of the body element must reflect the element's vlink content attribute.

[XXX] interface HTMLDocument {
           attribute DOMString fgColor;
           attribute DOMString bgColor;
           attribute DOMString linkColor;
           attribute DOMString vlinkColor;
           attribute DOMString alinkColor;
};

The fgColor attribute on the Document object must reflect the text attribute on the body element.

The bgColor attribute on the Document object must reflect the bgcolor attribute on the body element.

The linkColor attribute on the Document object must reflect the link attribute on the body element.

The vLinkColor attribute on the Document object must reflect the vlink attribute on the body element.

The aLinkColor attribute on the Document object must reflect the alink attribute on the body element.

11.4 Conformance checkers

To ease the transition from HTML4 Transitional documents to the language defined in this specification, conformance checkers are encouraged to categorise errors that represent usage of old obsolete features that generally have no effect (as defined below) into a separate part of their report, to allow authors to distinguish between likely mistakes and mere vestigial markup.

The following errors may be categorised as described above: