<mo>

The MathML <mo> element represents an operator in a broad sense. Besides operators in strict mathematical meaning, this element also includes "operators" like parentheses, separators like comma and semicolon, or "absolute value" bars.

Attributes

accent

If the operator is used as an under- or overscript this attribute specifies whether the operator should be treated as an accent. Allowed values are true or false.

class, id, style

Provided for use with stylesheets.

dir

The text direction. Possible values are either ltr (left to right) or rtl (right to left).

displaystyle

A Boolean value specifying whether more vertical space is used for displayed equations or, if set to false, a more compact layout is used to display formulas. The main effect is that larger versions of operators are displayed, when displaystyle is set to true. See also movablelimits on <mo>.

fence

There is no visual effect for this attribute, but it specifies whether the operator is a fence (such as parentheses). Allowed values are true or false.

href

Used to set a hyperlink to a specified URI.

lspace

The amount of space before the operator (see length for values and units). The constant thickmathspace (5/18em) is the default value.

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.

mathsize

The size of the content. See length for possible values. Deprecated values are: small, normal and big. These will be removed in the future.

mathvariant

This attribute specifies the logical class of the operator which varies in typography. That is, although the names suggest the typographic style for the class, semantically, items with the same class are treated "the same" within an expression, which might or might not involve displaying them with the named typography. The following values are allowed:

normal (Default value) ; $Example$
bold ; $Example$
italic ; $Example$
bold-italic ; $Example$

double-struck ; $Example$
bold-fraktur ; $Example$
script ; $Example$
bold-script ; $Example$
fraktur ; $Example$

sans-serif ; $Example$
bold-sans-serif ; $Example$
sans-serif-italic ; $Example$
sans-serif-bold-italic ; $Example$
monospace ; $Example$

initial ; $مثال$
tailed ; $مثال$
looped ; $مثال$
stretched ; $مثال$

maxsize

If stretchy is true, this attribute specifies the maximum size of the operator. Allowed values are:

infinity
an arbitrary length

minsize

If stretchy is true, this attribute specifies the minimum size of the operator. Allowed values are:

infinity
an arbitrary length

movablelimits

Specifies whether attached under- and overscripts move to sub- and superscript positions when displaystyle is false. Allowed values are either true or false.

rspace

The amount of space after the operator (see length for values and units). The constant thickmathspace (5/18em) is the default value.

separator

There is no visual effect for this attribute, but it specifies whether the operator is a separator (such as commas). Allowed values are true or false.

stretchy

Specifies whether the operator stretches to the size of the adjacent element. Allowed values are true or false.

symmetric

If stretchy is true, this attribute specifies whether the operator should be vertically symmetric around the imaginary math axis (centered fraction line). The default value is true if stretchy is set to true and otherwise false. Allowed values are true or false.

Examples

<math>

<mrow>
  <mn>5</mn>
  <mo>+</mo>
  <mn>5</mn>
</mrow>

<mrow>
  <mo> [ </mo> <!-- default form value: prefix -->
  <mrow>
    <mn> 0 </mn>
    <mo> ; </mo> <!-- default form value: infix -->
    <mn> 1 </mn>
  </mrow>
  <mo> ) </mo> <!-- default form value: postfix -->
</mrow>

</math>

Specifications

Specification
MathML Core # operator-fence-separator-or-accent-mo

Browser compatibility

BCD tables only load in the browser

Gecko-specific notes

Starting with Gecko 16.0 (Firefox 16.0 / Thunderbird 16.0 / SeaMonkey 2.13) the default values for lspace and rspace have been corrected to match the MathML3 specification. They now default to the constant thickmathspace (5/18em).
Some mathvariant values are only implemented starting with Gecko 28.0 (Firefox 28.0 / Thunderbird 28.0 / SeaMonkey 2.25) and require appropriate math fonts.
Any linebreaking or indentation attributes are not implemented yet. See bug 534962.