# [itex]

The top-level element in MathML is `[itex]`. Every valid MathML instance must be wrapped in `[itex]` tags. In addition you must not nest a second `[itex]` element in another, but you can have an arbitrary number of other child elements in it.

## Attributes

In addition to the following attributes, the `[itex]` element accepts any attributes of the `<mstyle>` element.

class, id, style
Provided for use with stylesheets.
dir
Overall directionality of formulas. Possible values are either `ltr` (left to right) or `rtl` (right to left).
href
Used to set a hyperlink to a specified URI.
mathbackground
The background color. You can use `#rgb`, `#rrggbb` and HTML color names.
mathcolor
The text color. You can use `#rgb`, `#rrggbb` and HTML color names.
display
This enumerated attribute specifies how the enclosed MathML markup should be rendered. It can have one of the following values:
• `block`, which means that this element will be displayed outside the current span of text, as a block that can be positioned anywhere without changing the meaning of the text;
• `inline`, which means that this element will be displayed inside the current span of text, and cannot be moved out of it without changing the meaning of that text.

If not present, its default value is `inline`.

mode
Deprecated in favor of the display attribute.
Possible values are: `display` (which has the same effect as `display="block"`) and `inline`.
overflow
Specifies how an expression behaves if it is too long to fit in the allowed width.
Possible values are: `linebreak` (default), `scroll`, `elide`, `truncate`, `scale`.

## Examples

### HTML5 notation

```<!DOCTYPE html>
<html>
<title>MathML in HTML5</title>
<body>

[itex]
<mrow>
<mrow>
<msup>
<mi>a</mi>
<mn>2</mn>
</msup>
<mo>+</mo>
<msup>
<mi>b</mi>
<mn>2</mn>
</msup>
</mrow>
<mo>=</mo>
<msup>
<mi>c</mi>
<mn>2</mn>
</msup>
</mrow>
[/itex]

</body>
</html>
```

### XHTML notation

```<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/xhtml-math11-f.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<title>MathML in XHTML</title>
<body>

<math xmlns="http://www.w3.org/1998/Math/MathML">
<mrow>
<mrow>
<msup>
<mi>a</mi>
<mn>2</mn>
</msup>
<mo>+</mo>
<msup>
<mi>b</mi>
<mn>2</mn>
</msup>
</mrow>
<mo>=</mo>
<msup>
<mi>c</mi>
<mn>2</mn>
</msup>
</mrow>
[/itex]

</body>
</html>```

Notes: XHTML documents with MathML must be served as `application/xhtml+xml`. You can achieve that easily by adding the `.xhtml` extension to your local files. For Apache servers you can configure your `.htaccess` file to map extensions to the correct Mime type. Since you notate your MathML in an XML document, also be sure you write a well-formed XML document.

## Specifications

Specification Status Comment
MathML 3.0
The definition of 'The Top-Level math Element' in that specification.
Recommendation Current specification
MathML 2.0
The definition of 'The Top-Level math Element' in that specification.
Recommendation Initial specification

## Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
XHTML notation No support 1.0 (1.7 or earlier) No support 9.5 5.1
HTML5 notation No support 4.0 (2.0) No support No support 5.1
`dir` No support 12.0 (12.0) No support No support No support
`href` No support 7.0 (7.0) No support No support No support [1]
`mathbackground` No support 4.0 (2.0) No support No support 5.1
`mathcolor` No support 4.0 (2.0) No support No support 5.1
`overflow` No support No support No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
XHTML notation No support No support 1.0 (1.0) No support No support No support
HTML5 notation No support No support 4.0 (2.0) No support No support No support
`dir` No support No support 12.0 (12.0) No support No support No support
`href` No support No support 7.0 (7.0) No support No support No support [1]
`mathbackground` No support No support 4.0 (2.0) No support No support No support
`mathcolor` No support No support 4.0 (2.0) No support No support No support
`overflow` No support No support No support No support No support No support

[1] See bug 85733.

## Gecko-specific notes

Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4) introduced support for accepting all MathML attributes on the top-level math element (i.e. the same behavior as a `<mstyle>` element). However, the `displaystyle` attribute was not taken into account and has been added in Gecko 8.0 (Firefox 8.0 / Thunderbird 8.0 / SeaMonkey 2.5).

A textual fall-back (`alttext`) or referring to an alternative image using the attributes `altimg`, `altimg-width`, `altimg-height` or `altimg-valign` is currently not implemented in Gecko.