HTML5 MathML id Attribute

Definition and usage

The id attribute is a global attribute available on every MathML element. Its value must be unique within the document. You can target the element with a CSS #id selector, retrieve it with document.getElementById, or reference it from another element.

Which elements use it

• Every MathML element accepts id, as it is a global attribute.

Example

<math>
  <mfrac id="halfFraction">
    <mn>1</mn>
    <mn>2</mn>
  </mfrac>
</math>

The fraction now has the id halfFraction, so CSS like #halfFraction { color: blue; } or scripting can target it directly.