# HTML5

## A vocabulary and associated APIs for HTML and XHTML

## Editor's Draft 22 August 2012

#### 4.6.15 The `sub`

and `sup`

elements

- Categories:
- Flow content.
- Phrasing content.
- Palpable content.
- Contexts in which this element can be used:
- Where phrasing content is expected.
- Content model:
- Phrasing content.
- Content attributes:
- Global attributes
- DOM interface:
- Use
`HTMLElement`

.

The `sup`

element represents a
superscript and the `sub`

element represents
a subscript.

These elements must be used only to mark up typographical
conventions with specific meanings, not for typographical
presentation for presentation's sake. For example, it would be
inappropriate for the `sub`

and `sup`

elements
to be used in the name of the LaTeX document preparation system. In
general, authors should use these elements only if the
*absence* of those elements would change the meaning of the
content.

In certain languages, superscripts are part of the typographical
conventions for some abbreviations.

<p>The most beautiful women are
<span lang="fr"><abbr>M<sup>lle</sup></abbr> Gwendoline</span> and
<span lang="fr"><abbr>M<sup>me</sup></abbr> Denise</span>.</p>

The `sub`

element can be used inside a
`var`

element, for variables that have subscripts.

Here, the `sub`

element is used to represents the
subscript that identifies the variable in a family of
variables:

<p>The coordinate of the <var>i</var>th point is
(<var>x<sub><var>i</var></sub></var>, <var>y<sub><var>i</var></sub></var>).
For example, the 10th point has coordinate
(<var>x<sub>10</sub></var>, <var>y<sub>10</sub></var>).</p>

Mathematical expressions often use subscripts and superscripts.
Authors are encouraged to use MathML for marking up mathematics, but
authors may opt to use `sub`

and `sup`

if
detailed mathematical markup is not desired. [MATHML]

<var>E</var>=<var>m</var><var>c</var><sup>2</sup>

f(<var>x</var>, <var>n</var>) = log<sub>4</sub><var>x</var><sup><var>n</var></sup>