WAI-ARIA: Role=Math
Content that represents a mathematical expression.
Description
Content that represents a mathematical expression.
Content with the role math is intended to be marked up in an accessible format such as MathML [MathML3], or with another type of textual representation such as TeX or LaTeX, which can be converted to an accessible format by native browser implementations or a polyfill library.
While it is not ideal to use an image of a mathematical expression, there exists a significant amount of legacy content where images are used to represent mathematical expressions. Authors SHOULD ensure that images of math are labeled by text that describes the mathematical expression as it might be spoken.
Note: Browsers that support native implementations of MathML are able to provide a more robust, accessible math experience than can be accomplished with plain text approximations of math. Some rendering engines have close integration with screen readers that allow spacial touch exploration of the formula and refreshable braille display output in the Nemeth Braille format. This level of integration is not supported with images of mathematical formulas, even if the author provides a plain text approximation.
At the time of this writing, some mainstream browsers do not support MathML natively, and must be retrofit using a JavaScript polyfill library. When authoring math content, use native MathML wherever possible, and test thoroughly. Use a polyfill library or provide a fallback image with a text alternative approximation if necessary.
Role=Math Example
MathML Example with Embedded TeX Annotation
Note: Use a JavaScript polyfill library to ensure this renders in user agents that do not support MathML. The math element has an implicit role=”math”.
<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>x</mi><mo>=</mo><mfrac><mrow><mo form="prefix">−</mo><mi>b</mi><mo>±</mo><msqrt><msup><mi>b</mi><mn>2</mn></msup><mo>−</mo><mn>4</mn><mo>⁢<!-- ⁢ --></mo><mi>a</mi><mo>⁢<!-- ⁢ --></mo><mi>c</mi></msqrt></mrow><mrow><mn>2</mn><mo>⁢<!-- ⁢ --></mo><mi>a</mi></mrow></mfrac></mrow><annotation encoding="TeX">x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}</annotation></math>Plain HTML or Polyfill DOM Result of the MathML Quadratic Formula
If a rendering engine does not support a native math format such as MathML, authors MAY use JavaScript to downgrade the content to a format the browser can display, such as this HTML image using a data URI and plain text alternative.
<img role="math" src="/..." alt="x=⟮−b±√⟮b²−4ac⟯⟯÷2a">
HTML Example
- math: Content that represents a mathematical expression.
- aria-label: Defines a string value that labels the current element.
- All other content in this example is MathML
<div role="math" aria-label="6 divided by 4 equals 1.5"><math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>6</mn><mn>4</mn></mfrac><mo>=</mo><mn>1.5</mn></math></div>
Characteristics
Superclass Role
- section
Inherited States and Properties
- aria-atomic
- aria-busy (state)
- aria-controls
- aria-current (state)
- aria-describedby
- aria-details
- aria-disabled (state)
- aria-dropeffect
- aria-errormessage
- aria-expanded (state)
- aria-flowto
- aria-grabbed (state)
- aria-haspopup
- aria-hidden (state)
- aria-invalid (state)
- aria-keyshortcuts
- aria-label
- aria-labelledby
- aria-live
- aria-owns
- aria-relevant
- aria-roledescription
Name From
- author
Children Presentational
- True
Semantic HTML
Use the HTML5 <math> tag.
<math><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></math>
Reference
W3C (opens new window)
