HTML5

However it is implemented, drag-and-drop operations must have a starting point (e.g. where the mouse was clicked, or the start of the selection or element that was selected for the drag), may have any number of intermediate steps (elements that the mouse moves over during a drag, or elements that the user picks as possible drop points as he cycles through possibilities), and must either have an end point (the element above which the mouse button was released, or the element that was finally selected), or be canceled. The end point must be the last element selected as a possible drop point before the drop occurs (so if the operation is not canceled, there must be at least one element in the middle step).

<p>What fruits do you like?</p>
<ol ondragstart="dragStartHandler(event)">
 <li draggable="true" data-value="fruit-apple">Apples</li>
 <li draggable="true" data-value="fruit-orange">Oranges</li>
 <li draggable="true" data-value="fruit-pear">Pears</li>
</ol>
<script>
  var internalDNDType = 'text/x-example'; // set this to something specific to your site
  function dragStartHandler(event) {
    if (event.target instanceof HTMLLIElement) {
      // use the element's data-value="" attribute as the value to be moving:
      event.dataTransfer.setData(internalDNDType, event.target.dataset.value);
      event.dataTransfer.effectAllowed = 'move'; // only allow moves
    } else {
      event.preventDefault(); // don't allow selection to be dragged
    }
  }
</script>

<p>Drop your favorite fruits below:</p>
<ol dropzone="move s:text/x-example" ondrop="dropHandler(event)">
 <-- don't forget to change the "text/x-example" type to something
 specific to your site -->
</ol>
<script>
  var internalDNDType = 'text/x-example'; // set this to something specific to your site
  function dropHandler(event) {
    var li = document.createElement('li');
    var data = event.dataTransfer.getData(internalDNDType);
    if (data == 'fruit-apple') {
      li.textContent = 'Apples';
    } else if (data == 'fruit-orange') {
      li.textContent = 'Oranges';
    } else if (data == 'fruit-pear') {
      li.textContent = 'Pears';
    } else {
      li.textContent = 'Unknown Fruit';
    }
    event.target.appendChild(li);
  }
</script>

<p>What fruits do you like?</p>
<ol ondragstart="dragStartHandler(event)" ondragend="dragEndHandler(event)">
 ...as before...
</ol>
<script>
  function dragStartHandler(event) {
    // ...as before...
  }
  function dragEndHandler(event) {
    // remove the dragged element
    event.target.parentNode.removeChild(event.target);
  }
</script>

interface DataTransfer {
           attribute DOMString dropEffect;
           attribute DOMString effectAllowed;

  readonly attribute DataTransferItems items;

  void setDragImage(in Element image, in long x, in long y);
  void addElement(in Element element);

  /* old interface */
  readonly attribute DOMStringList types;
  DOMString getData(in DOMString format);
  void setData(in DOMString format, in DOMString data);
  void clearData(in optional DOMString format);
  readonly attribute FileList files;
};

A DataTransfer object is associated with a drag data store while it is valid.

The dropEffect attribute controls the drag-and-drop feedback that the user is given during a drag-and-drop operation. When the DataTransfer object is created, the dropEffect attribute is set to a string value. On getting, it must return its current value. On setting, if the new value is one of "none", "copy", "link", or "move", then the attribute's current value must be set to the new value. Other values must be ignored.

The effectAllowed attribute is used in the drag-and-drop processing model to initialize the dropEffect attribute during the dragenter and dragover events. When the DataTransfer object is created, the effectAllowed attribute is set to a string value. On getting, it must return its current value. On setting, if the new value is one of "none", "copy", "copyLink", "copyMove", "link", "linkMove", "move", "all", or "uninitialized", then the attribute's current value must be set to the new value. Other values must be ignored.

The items attribute must return a DataTransferItems object associated with the DataTransfer object. The same object must be returned each time.

The setDragImage(element, x, y) method must run the following steps:

1. If the DataTransfer object is no longer associated with a drag data store, abort these steps. Nothing happens.

2. If the drag data store's mode is not in the read/write mode, abort these steps. Nothing happens.

3. If the element argument is an img element, then set the drag data store bitmap to the element's image (at its intrinsic size); otherwise, set the drag data store bitmap to an image generated from the given element (the exact mechanism for doing so is not currently specified).

4. Set the drag data store hot spot coordinate to the given x, y coordinate.

The addElement(element) method is an alternative way of specifying how the user agent is to render the drag feedback. The method must run the following steps:

1. If the DataTransfer object is no longer associated with a drag data store, abort these steps. Nothing happens.

2. If the drag data store's mode is not in the read/write mode, abort these steps. Nothing happens.

3. Add the given element to the element's drag data store elements list.

The difference between setDragImage() and addElement() is that the latter automatically generates the image based on the current rendering of the elements added (potentially keeping it updated as the drag continues, e.g. if the elements include an actively playing video), whereas the former uses the exact specified image at the time the method is invoked.

The types attribute must return a live DOMStringList giving the strings that the following steps would produce. The same object must be returned each time.

1. Start with an empty list L.

2. If the DataTransfer object is no longer associated with a drag data store, the DOMStringList is empty. Abort these steps; return the empty list L.

3. For each item in the drag data store item list whose kind is Plain Unicode string, add an entry to the list L consisting of the item's type string.

4. If there are any items in the drag data store item list whose kind is File, then add an entry to the list L consisting of the string "Files". (This value can be distinguished from the other values because it is not lowercase.)

5. The strings produced by these steps are those in the list L.

The getData(format) method must run the following steps:

1. If the DataTransfer object is no longer associated with a drag data store, return the empty string and abort these steps.

2. If the drag data store's mode is in the protected mode, return the empty string and abort these steps.

3. Let format be the first argument, converted to ASCII lowercase.

4. Let convert-to-URL be false.

5. If format equals "text", change it to "text/plain".

6. If format equals "url", change it to "text/uri-list" and set convert-to-URL to true.

7. If there is no item in the drag data store item list whose kind is Plain Unicode string and whose type string is equal to format, return the empty string and abort these steps.

8. Let result be the data of the item in the drag data store item list whose kind is Plain Unicode string and whose type string is equal to format.

9. If convert-to-URL is true, then parse result as appropriate for text/uri-list data, and then set result to the first URL from the list, if any, or the empty string otherwise. [RFC2483]

10. Return result.

The setData(format, data) method must run the following steps:

1. If the DataTransfer object is no longer associated with a drag data store, abort these steps. Nothing happens.

2. If the drag data store's mode is not the read/write mode, abort these steps. Nothing happens.

3. Let format be the first argument, converted to ASCII lowercase.

4. If format equals "text", change it to "text/plain".

   If format equals "url", change it to "text/uri-list".

5. Remove the item in the drag data store item list whose kind is Plain Unicode string and whose type string is equal to format, if there is one.

6. Add an item to the drag data store item list whose kind is Plain Unicode string, whose type string is equal to format, and whose data is the string given by the method's second argument.

The clearData() method must run the following steps:

1. If the DataTransfer object is no longer associated with a drag data store, abort these steps. Nothing happens.

2. If the drag data store's mode is not the read/write mode, abort these steps. Nothing happens.

3. If the method was called with no arguments, remove each item in the drag data store item list whose kind is Plain Unicode string, and abort these steps.

4. Let format be the first argument, converted to ASCII lowercase.

5. If format equals "text", change it to "text/plain".

   If format equals "url", change it to "text/uri-list".

6. Remove the item in the drag data store item list whose kind is Plain Unicode string and whose type string is equal to format, if there is one.

The clearData() method does not affect whether any files were included in the drag, so the types attribute's list might still not be empty after calling clearData() (it would still contain the "Files" string if any files were included in the drag).

The files attribute must return a live FileList sequence consisting of File objects representing the files found by the following steps. The same object must be returned each time. Furthermore, for a given FileList object and a given underlying file, the same File object must be used each time.

1. Start with an empty list L.

2. If the DataTransfer object is no longer associated with a drag data store, the FileList is empty. Abort these steps; return the empty list L.

3. If the drag data store's mode is in the protected mode, abort these steps; return the empty list L.

4. For each item in the drag data store item list whose kind is File , add the item's data (the file, in particular its name and contents, as well as its type) to the list L.

5. The files found by these steps are those in the list L.

This version of the API does not expose the types of the files during the drag.

interface DataTransferItems {
  readonly attribute unsigned long length;
  getter DataTransferItem (in unsigned long index);
  deleter void (in unsigned long index);
  void clear();

  DataTransferItem add(in DOMString data, in DOMString type);  DataTransferItem add(in File data);};

While the DataTransferItems object's DataTransfer object is associated with a drag data store, the DataTransferItems object's mode is the same as the drag data store mode. When the DataTransferItems object's DataTransfer object is not associated with a drag data store, the DataTransferItems object's mode is the disabled mode. The drag data store referenced in this section (which is used only when the DataTransferItems object is not in the disabled mode) is the drag data store with which the DataTransferItems object's DataTransfer object is associated.

The length attribute must return zero if the object is in the disabled mode; otherwise it must return the number of items in the drag data store item list.

When a DataTransferItems object is not in the disabled mode, its supported property indices are the numbers in the range 0 .. n-1, where n is the number of items in the drag data store item list.

To determine the value of an indexed property i of a DataTransferItems object, the user agent must return a DataTransferItem object representing the ith item in the drag data store. The same object must be returned each time a particular item is obtained from this DataTransferItems object. The DataTransferItem object must be associated with the same DataTransfer object as the DataTransferItems object when it is first created.

To delete an existing indexed property i of a DataTransferItems object, the user agent must run these steps:

1. If the DataTransferItems object is not in the read/write mode, throw an INVALID_STATE_ERR exception and abort these steps.

2. Remove the ith item from the drag data store.

The clear method, if the DataTransferItems object is in the read/write mode, must remove all the items from the drag data store. Otherwise, it must do nothing.

The add() method must run the following steps:

1. If the DataTransferItems object is not in the read/write mode, return null and abort these steps.

2. Jump to the appropriate set of steps from the following list:

   If the first argument to the method is a string

   If there is already an item in the drag data store item list whose kind is Plain Unicode string and whose type string is equal to the value of the method's second argument, converted to ASCII lowercase, then throw a NOT_SUPPORTED_ERR exception and abort these steps.

   Otherwise, add an item to the drag data store item list whose kind is Plain Unicode string, whose type string is equal to the value of the method's second argument, converted to ASCII lowercase, and whose data is the string given by the method's first argument.

   If the first argument to the method is a File

   Add an item to the drag data store item list whose kind is File, whose type string is the type of the File, converted to ASCII lowercase, and whose data is the same as the File's data.

3. Determine the value of the indexed property corresponding to the newly added item, and return that value (a newly created DataTransferItem object).

interface DataTransferItem {
    readonly attribute DOMString kind;
    readonly attribute DOMString type;
    void getAsString(in FunctionStringCallback callback);    File getAsFile();};

[Callback=FunctionOnly, NoInterfaceObject]
interface FunctionStringCallback {
  void handleEvent(in DOMString data);
};

While the DataTransferItem object's DataTransfer object is associated with a drag data store and that drag data store's drag data store item list still contains the item that the DataTransferItem object represents, the DataTransferItem object's mode is the same as the drag data store mode. When the DataTransferItem object's DataTransfer object is not associated with a drag data store, or if the item that the DataTransferItem object represents has been removed from the relevant drag data store item list, the DataTransferItem object's mode is the disabled mode. The drag data store referenced in this section (which is used only when the DataTransferItem object is not in the disabled mode) is the drag data store with which the DataTransferItem object's DataTransfer object is associated.

The kind attribute must return the empty string if the DataTransferItem object is in the disabled mode; otherwise it must return the string given in the cell from the second column of the following table from the row whose cell in the first column contains the drag data item kind of the item represented by the DataTransferItem object:

Kind	String
Plain Unicode string	"string"
File	"file"

The type attribute must return the empty string if the DataTransferItem object is in the disabled mode; otherwise it must return the drag data item type string of the item represented by the DataTransferItem object.

The getAsString(callback) method must run the following steps:

1. If the callback is null, abort these steps.

2. If the DataTransferItem object is not in the read/write mode or the read-only mode, abort these steps. The callback is never invoked.

3. If the drag data item kind is not Plain Unicode string, abort these steps. The callback is never invoked.

4. Otherwise, queue a task to invoke callback, passing the actual data of the item represented by the DataTransferItem object as the argument.

The getAsFile() method must run the following steps:

1. If the DataTransferItem object is not in the read/write mode or the read-only mode, return null and abort these steps.

2. If the drag data item kind is not File, then return null and abort these steps.

3. Return a new File object representing the actual data of the item represented by the DataTransferItem object.

interface DragEvent : MouseEvent {
  readonly attribute DataTransfer dataTransfer;

  void initDragEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean cancelableArg, in any dummyArg, in long detailArg, in long screenXArg, in long screenYArg, in long clientXArg, in long clientYArg, in boolean ctrlKeyArg, in boolean altKeyArg, in boolean shiftKeyArg, in boolean metaKeyArg, in unsigned short buttonArg, in EventTarget relatedTargetArg, in DataTransfer dataTransferArg);
};

The initDragEvent() method must initialize the event in a manner analogous to the similarly-named method in the DOM Events interfaces, except that the dummyArg argument must be ignored. [DOMEVENTS]

The dataTransfer attribute of the DragEvent interface represents the context information for the event.

When a user agent is required to fire a DND event named e at an element, using a particular drag data store, the user agent must run the following steps:

1. If e is dragstart, set the drag data store mode to the read/write mode.

   If e is drop, set the drag data store mode to the read-only mode.

2. Let dataTransfer be a newly created DataTransfer object associated with the given drag data store.

3. Set the effectAllowed attribute to the drag data store's drag data store allowed effects state.

4. Set the dropEffect attribute to "none" if e is dragstart, drag, or dragleave; to the value corresponding to the current drag operation if e is drop or dragend; and to a value based on the effectAllowed attribute's value and to the drag-and-drop source, as given by the following table, otherwise (i.e. if e is dragenter or dragover):

   effectAllowed	dropEffect
   "none"	"none"
   "copy", "copyLink", "copyMove", "all"	"copy"
   "link", "linkMove"	"link"
   "move"	"move"
   "uninitialized" when what is being dragged is a selection from a text field	"move"
   "uninitialized" when what is being dragged is a selection	"copy"
   "uninitialized" when what is being dragged is an a element with an href attribute	"link"
   Any other case	"copy"

5. Create a DragEvent object and initialize it to have the given name e, to bubble, to be cancelable unless e is dragleave or dragend, and to have the detail attribute set to zero, the mouse and key attributes set according to the state of the input devices as they would be for user interaction events, the relatedTarget attribute set to null, and the dataTransfer attribute set to dataTransfer, the DataTransfer object created above.

   If there is no relevant pointing device, the object must have its screenX, screenY, clientX, clientY, and button attributes set to 0.

6. Dispatch the newly created DragEvent object at the specified target element.

7. Set the drag data store allowed effects state to the current value of dataTransfer's effectAllowed attribute.

8. Set the drag data store mode back to the protected mode if it was changed in the first step.

9. Break the association between dataTransfer and the drag data store.

7.7.5 Drag-and-drop processing model

When the user attempts to begin a drag operation, the user agent must run the following steps. User agents must act as if these steps were run even if the drag actually started in another document or application and the user agent was not aware that the drag was occuring until it intersected with a document under the user agent's purview.

1. Determine what is being dragged, as follows:

   If the drag operation was invoked on a selection, then it is the selection that is being dragged.

   Otherwise, if the drag operation was invoked on a Document, it is the first element, going up the ancestor chain, starting at the node that the user tried to drag, that has the IDL attribute draggable set to true. If there is no such element, then nothing is being dragged; abort these steps, the drag-and-drop operation is never started.

   Otherwise, the drag operation was invoked outside the user agent's purview. What is being dragged is defined by the document or application where the drag was started.

   img elements and a elements with an href attribute have their draggable attribute set to true by default.

2. Create a drag data store. All the DND events fired subsequently by the steps in this section must use this drag data store.

3. Establish which DOM node is the source node, as follows:

   If it is a selection that is being dragged, then the source node is the text node that the user started the drag on (typically the text node that the user originally clicked). If the user did not specify a particular node, for example if the user just told the user agent to begin a drag of "the selection", then the source node is the first text node containing a part of the selection.

   Otherwise, if it is an element that is being dragged, then the source node is the element that is being dragged.

   Otherwise, the source node is part of another document or application. When this specification requires that an event be dispatched at the source node in this case, the user agent must instead follow the platform-specific conventions relevant to that situation.

   Multiple events are fired on the source node during the course of the drag-and-drop operation.

4. Determine the list of dragged nodes, as follows:

   If it is a selection that is being dragged, then the list of dragged nodes contains, in tree order, every node that is partially or completely included in the selection (including all their ancestors).

   Otherwise, the list of dragged nodes contains only the source node, if any.

5. If it is a selection that is being dragged, then add an item to the drag data store item list, with its properties set as follows:

   The drag data item type string

   "text/plain"

   The drag data item kind

   Plain Unicode string

   The actual data

   The text of the selection

   Otherwise, if any files are being dragged, then add one item per file to the drag data store item list, with their properties set as follows:

   The drag data item type string

   The MIME type of the file, if known, or "application/octet-stream" otherwise.

   The drag data item kind

   File

   The actual data

   The file's contents and name.

   Dragging files can currently only happen from outside a browsing context, for example from a file system manager application.

   If the drag initiated outside of the application, the user agent must add items to the drag data store item list as appropriate for the data being dragged, honoring platform conventions where appropriate; however, if the platform conventions do not use MIME types to label dragged data, the user agent must make a best-effort attempt to map the types to MIME types, and, in any case, all the drag data item type strings must be converted to ASCII lowercase.

6. Perform drag-and-drop initialization steps defined in any other applicable specifications.

7. Run the following substeps:

   1. Let urls be an empty list of absolute URLs.

   2. For each node in the list of dragged nodes:

      If the node is an a element with an href attribute

      Add to urls the result of resolving the element's href content attribute relative to the element.

      If the node is an img element with an src attribute

      Add to urls the result of resolving the element's src content attribute relative to the element.

   3. If urls is still empty, abort these substeps.

   4. Let url string be the result of concatenating the strings in urls, in the order they were added, separated by a U+000D CARRIAGE RETURN U+000A LINE FEED character pair (CRLF).

   5. Add one item to the drag data store item list, with its properties set as follows:

      The drag data item type string

      text/uri-list

      The drag data item kind

      Plain Unicode string

      The actual data

      url string

8. If it is an element that is being dragged, then set the drag data store elements list to contain just the source node.

   Otherwise, update the drag data store default feedback as appropriate for the user agent (if the user is dragging the selection, then the selection would likely be the basis for this feedback; if the drag began outside the user agent, then the platform conventions for determining the drag feedback should be used).

   Script can use the addElement() method to add further elements to the list of what is being dragged. (This list is only used for rendering the drag feedback.)

9. Fire a DND event named dragstart at the source node.

   If the event is canceled, then the drag-and-drop operation should not occur; abort these steps.

   Since events with no event listeners registered are, almost by definition, never canceled, drag-and-drop is always available to the user if the author does not specifically prevent it.

10. Initiate the drag-and-drop operation in a manner consistent with platform conventions, and as described below.

    The drag-and-drop feedback must be generated from the first of the following sources that is available:

    1. The drag data store bitmap, if any. In this case, the drag data store hot spot coordinate should be used as hints for where to put the cursor relative to the resulting image. The values are expressed as distances in CSS pixels from the left side and from the top side of the image respectively. [CSS]
    2. The elements in the drag data store elements list, if any.
    3. The drag data store default feedback.

From the moment that the user agent is to initiate the drag-and-drop operation, until the end of the drag-and-drop operation, device input events (e.g. mouse and keyboard events) must be suppressed. In addition, the user agent must track all DOM changes made during the drag-and-drop operation, and add them to its undo transaction history as one atomic operation once the drag-and-drop operation has ended.

During the drag operation, the element directly indicated by the user as the drop target is called the immediate user selection. (Only elements can be selected by the user; other nodes must not be made available as drop targets.) However, the immediate user selection is not necessarily the current target element, which is the element currently selected for the drop part of the drag-and-drop operation.

The immediate user selection changes as the user selects different elements (either by pointing at them with a pointing device, or by selecting them in some other way). The current target element changes when the immediate user selection changes, based on the results of event listeners in the document, as described below.

Both the current target element and the immediate user selection can be null, which means no target element is selected. They can also both be elements in other (DOM-based) documents, or other (non-Web) programs altogether. (For example, a user could drag text to a word-processor.) The current target element is initially null.

In addition, there is also a current drag operation, which can take on the values "none", "copy", "link", and "move". Initially, it has the value "none". It is updated by the user agent as described in the steps below.

User agents must, as soon as the drag operation is initiated and every 350ms (±200ms) thereafter for as long as the drag operation is ongoing, queue a task to perform the following steps in sequence:

1. If the user agent is still performing the previous iteration of the sequence (if any) when the next iteration becomes due, abort these steps for this iteration (effectively "skipping missed frames" of the drag-and-drop operation).

2. Fire a DND event named drag event at the source node. If this event is canceled, the user agent must set the current drag operation to "none" (no drag operation).

3. If the drag event was not canceled and the user has not ended the drag-and-drop operation, check the state of the drag-and-drop operation, as follows:

   1. If the user is indicating a different immediate user selection than during the last iteration (or if this is the first iteration), and if this immediate user selection is not the same as the current target element, then update the current target element as follows:

      If the new immediate user selection is null

      Set the current target element to null also.

      If the new immediate user selection is in a non-DOM document or application

      Set the current target element to the immediate user selection.

      Otherwise

      Fire a DND event named dragenter at the immediate user selection.

      If the event is canceled, then set the current target element to the immediate user selection.

      Otherwise, run the appropriate step from the following list:

      If the current target element is a text field (e.g. textarea, or an input element whose type attribute is in the Text state) or an editable element, and the drag data store item list has an item with the drag data item type string "text/plain" and the drag data item kind Plain Unicode string

      Set the current target element to the immediate user selection anyway.

      If the current target element is an element with a dropzone attribute that matches the drag data store

      Set the current target element to the immediate user selection anyway.

      If the current target element is the body element

      Leave the current target element unchanged.

      Otherwise

      Fire a DND event named dragenter at the body element, and set the current target element to the body element, regardless of whether that event was canceled or not.

      If the body element is null, then the event will be fired at the Document object (as required by the definition of the body element), but the current target element would be set to null, not the Document object.

   2. If the previous step caused the current target element to change, and if the previous target element was not null or a part of a non-DOM document, then fire a DND event named dragleave at the previous target element.

   3. If the current target element is a DOM element, then fire a DND event named dragover at this current target element.

      If the dragover event is not canceled, run the appropriate step from the following list:

      If the current target element is a text field (e.g. textarea, or an input element whose type attribute is in the Text state) or an editable element, and the drag data store item list has an item with the drag data item type string "text/plain" and the drag data item kind Plain Unicode string

      Set the current drag operation to either "copy" or "move", as appropriate given the platform conventions.

      If the current target element is an element with a dropzone attribute that matches the drag data store and specifies an operation

      Set the current drag operation to the operation specified by the dropzone attribute of the current target element.

      If the current target element is an element with a dropzone attribute that matches the drag data store and does not specify an operation

      Set the current drag operation to "copy".

      Otherwise

      Reset the current drag operation to "none".

      Otherwise (if the dragover event is canceled), set the current drag operation based on the values of the effectAllowed and dropEffect attributes of the DragEvent object's dataTransfer object as they stood after the event dispatch finished, as per the following table:

      effectAllowed	dropEffect	Drag operation
      "uninitialized", "copy", "copyLink", "copyMove", or "all"	"copy"	"copy"
      "uninitialized", "link", "copyLink", "linkMove", or "all"	"link"	"link"
      "uninitialized", "move", "copyMove", "linkMove", or "all"	"move"	"move"
      Any other case		"none"

   4. Otherwise, if the current target element is not a DOM element, use platform-specific mechanisms to determine what drag operation is being performed (none, copy, link, or move), and set the current drag operation accordingly.

   5. Update the drag feedback (e.g. the mouse cursor) to match the current drag operation, as follows:

      Drag operation	Feedback
      "copy"	Data will be copied if dropped here.
      "link"	Data will be linked if dropped here.
      "move"	Data will be moved if dropped here.
      "none"	No operation allowed, dropping here will cancel the drag-and-drop operation.

4. Otherwise, if the user ended the drag-and-drop operation (e.g. by releasing the mouse button in a mouse-driven drag-and-drop interface), or if the drag event was canceled, then this will be the last iteration. Run the following steps, then stop the drag-and-drop operation:

   1. If the current drag operation is "none" (no drag operation), or, if the user ended the drag-and-drop operation by canceling it (e.g. by hitting the Escape key), or if the current target element is null, then the drag operation failed. Run these substeps:

      1. Let dropped be false.

      2. If the current target element is a DOM element, fire a DND event named dragleave at it; otherwise, if it is not null, use platform-specific conventions for drag cancellation.

      Otherwise, the drag operation was as success; run these substeps:

      1. Let dropped be true.

      2. If the current target element is a DOM element, fire a DND event named drop at it; otherwise, use platform-specific conventions for indicating a drop.

      3. If the event is canceled, set the current drag operation to the value of the dropEffect attribute of the DragEvent object's dataTransfer object as it stood after the event dispatch finished.

         Otherwise, the event is not canceled; perform the event's default action, which depends on the exact target as follows:

         If the current target element is a text field (e.g. textarea, or an input element whose type attribute is in the Text state) or an editable element, and the drag data store item list has an item with the drag data item type string "text/plain" and the drag data item kind Plain Unicode string

         Insert the actual data of the first item in the drag data store item list to have a drag data item type string of "text/plain" and a drag data item kind that is Plain Unicode string into the text field or editable element in a manner consistent with platform-specific conventions (e.g. inserting it at the current mouse cursor position, or inserting it at the end of the field).

         Otherwise

         Reset the current drag operation to "none".

   2. Fire a DND event named dragend at the source node.

   3. Run the appropriate steps from the following list as the default action of the dragend event:

      If the current target element is a text field (e.g. textarea, or an input element whose type attribute is in the Text state), and dropped is true, and the current drag operation is "move", and the source of the drag-and-drop operation is a selection in the DOM

      The user agent should delete the range representing the dragged selection from the DOM.

      If the current target element is a text field (e.g. textarea, or an input element whose type attribute is in the Text state), and dropped is true, and the current drag operation is "move", and the source of the drag-and-drop operation is a selection in a text field

      The user agent should delete the dragged selection from the relevant text field.

      Otherwise

      The event has no default action.

User agents are encouraged to consider how to react to drags near the edge of scrollable regions. For example, if a user drags a link to the bottom of the viewport on a long page, it might make sense to scroll the page so that the user can drop the link lower on the page.

This model is independent of which Document object the nodes involved are from; the events are fired as described above and the rest of the processing model runs as described above, irrespective of how many documents are involved in the operation.

The draggable IDL attribute, whose value depends on the content attribute's in the way described below, controls whether or not the element is draggable. Generally, only text selections are draggable, but elements whose draggable IDL attribute is true become draggable as well.

If an element's draggable content attribute has the state true, the draggable IDL attribute must return true.

Otherwise, if the element's draggable content attribute has the state false, the draggable IDL attribute must return false.

Otherwise, the element's draggable content attribute has the state auto. If the element is an img element, or, if the element is an a element with an href content attribute, the draggable IDL attribute must return true.

Otherwise, the draggable DOM must return false.

If the draggable IDL attribute is set to the value false, the draggable content attribute must be set to the literal value false. If the draggable IDL attribute is set to the value true, the draggable content attribute must be set to the literal value true.

A dropzone attribute matches a drag data store if the dropzone processing steps result in a match.

A dropzone attribute specifies an operation if the dropzone processing steps result in a specified operation. The specified operation is as given by those steps.

The dropzone processing steps are as follows. They either result in a match or not, and separate from this result either in a specified operation or not, as defined below.

1. Let value be the value of the dropzone attribute.

2. Let keywords be the result of splitting value on spaces.

3. Let matched be false.

4. Let operation be unspecified.

5. For each value in keywords, if any, in the order that they were found in value, run the following steps.

   1. Let keyword be the keyword.

   2. If keyword is one of "copy", "move", or "link", then: run the following substeps:

      1. If operation is still unspecified, then let operation be the string given by keyword.

      2. Skip to the step labeled end of keyword below.

   3. If keyword is shorter than three characters in length, then skip to the step labeled end of keyword below.

   4. If the second character in keyword is not a U+003A COLON character (:), then skip to the step labeled end of keyword below.

   5. Let kind code be the first character in keyword, converted to ASCII lowercase.

   6. Jump to the appropriate step from the list below, based on the value of kind code:

      If kind code is a U+0073 LATIN SMALL LETTER S character

      Let kind be Plain Unicode string.

      If kind code is a U+0066 LATIN SMALL LETTER F character

      Let kind be File.

      Otherwise

      Skip to the step labeled end of keyword below.

   7. Let type be the string consisting of all but the first two characters of keyword, converted to ASCII lowercase.

   8. If there exist any items in the drag data store item list whose drag data item kind is the kind given in kind and whose drag data item type is type, then let matched be true.

   9. End of keyword: Go on to the next keyword, if any, or the next step in the overall algorithm, if there are no more.

6. The algorithm results in a match if matched is true, and does not otherwise.

   The algorithm results in a specified operation if operation is not unspecified. The specified operation, if one is specified, is the one given by operation.

The dropzone IDL attribute must reflect the content attribute of the same name.

<div dropzone="copy f:image/png f:image/gif f:image/jpeg" ondrop="receive(event, this)">
 <p>Drop an image here to have it displayed.</p>
</div>
<script>
 function receive(event, element) {
   var data = event.dataTransfer.items;
   for (var i = 0; i < data.length; i += 1) {
     if ((data[i].kind == 'file') && (data[i].type.match('^image/'))) {
       var img = new Image();
       img.src = window.createObjectURL(data[i].getAsFile());
       element.appendChild(img);
     }
   }
 }
</script>

7.7.9 Security risks in the drag-and-drop model

User agents must not make the data added to the DataTransfer object during the dragstart event available to scripts until the drop event, because otherwise, if a user were to drag sensitive information from one document to a second document, crossing a hostile third document in the process, the hostile document could intercept the data.

For the same reason, user agents must consider a drop to be successful only if the user specifically ended the drag operation — if any scripts end the drag operation, it must be considered unsuccessful (canceled) and the drop event must not be fired.

User agents should take care to not start drag-and-drop operations in response to script actions. For example, in a mouse-and-window environment, if a script moves a window while the user has his mouse button depressed, the UA would not consider that to start a drag. This is important because otherwise UAs could cause data to be dragged from sensitive sources and dropped into hostile documents without the user's consent.

The execCommand(commandId, showUI, value) method on the HTMLDocument interface allows scripts to perform actions on the current selection or at the current caret position. Generally, these commands would be used to implement editor UI, for example having a "delete" button on a toolbar.

There are three variants to this method, with one, two, and three arguments respectively. The showUI and value parameters, even if specified, are ignored except where otherwise stated.

When execCommand() is invoked, the user agent must run the following steps:

1. If the given commandId maps to an entry in the list below whose "Enabled When" entry has a condition that is currently false, do nothing; abort these steps.
2. Otherwise, execute the "Action" listed below for the given commandId.

The queryCommandEnabled(commandId) method, when invoked, must return true if the condition listed below under "Enabled When" for the given commandId is true, and false otherwise.

The queryCommandIndeterm(commandId) method, when invoked, must return true if the condition listed below under "Indeterminate When" for the given commandId is true, and false otherwise.

The queryCommandState(commandId) method, when invoked, must return the value expressed below under "State" for the given commandId.

The queryCommandSupported(commandId) method, when invoked, must return true if the given commandId is in the list below, and false otherwise.

The queryCommandValue(commandId) method, when invoked, must return the value expressed below under "Value" for the given commandId.