HTML5 MathML
HTML5 MathML open Attribute
The open attribute specifies the opening fence character used by the <mfenced> element - for example ( or [. It pairs with the close attribute.
Definition and usage
The open attribute is applied to <mfenced> to choose the character that opens the fenced group. By default it is a left parenthesis. Common values include (, [, { and |.
Which elements use it
- <mfenced> - sets the opening bracket of the fence group.
Example
<math>
<mfenced open="{" close="}">
<mi>a</mi>
<mi>b</mi>
</mfenced>
</math>Here open="{" renders a curly opening brace before the content, giving {a b}.
⚠️
Because <mfenced> is deprecated and absent from MathML Core, the open attribute has limited support. Prefer an explicit opening <mo>{</mo> operator inside an <mrow>.