The term MathML element refers to any element in the
MathML namespace.
The MathML elements defined in this specification are called the
MathML Core elements and are listed below.
Any MathML element that is not listed below is called an
Unknown MathML element.
annotationannotation-xmlmactionmathmerrormfracmimmultiscriptsmnmomovermpaddedmphantommprescriptsmrootmrowmsmspacemsqrtmstylemsubmsubsupmsupmtablemtdmtextmtrmundermunderoversemantics
The grouping elements are
maction,
math,
merror,
mphantom,
mprescripts,
mrow,
mstyle,
semantics and unknown MathML elements.
The scripted elements are
mmultiscripts,
mover,
msub,
msubsup,
msup,
munder and
munderover.
The radical elements are
mroot and msqrt.
The attributes defined in this specification have no namespace
and are called MathML attributes:
MathML specifies a single top-level or root
math element, which encapsulates each
instance of MathML markup within a document. All other MathML content
must be contained in a <math> element.
The <math>
element accepts the attributes described
in 2.1.3 Global Attributes as well as the
following attributes:
The
display
attribute, if present,
must be an
ASCII case-insensitive
match
to block or inline.
The user agent stylesheet
described in A. User Agent Stylesheet
contains rules for this attribute that affect the
default values for the display
(block math or inline math)
and math-style
(normal or compact) properties.
If the display
attribute is absent or has an invalid value, the User Agent
stylesheet treats it the same as inline.
This specification does not define any observable behavior that is
specific to the alttext attribute.
Note
The
alttext attribute may be used as
alternative text by some legacy systems that do not
implement math layout.
If the <math> element does not have its computed
display property equal to
block math or inline math
then it is laid out according to the CSS specification where
the corresponding value is described.
Otherwise the layout algorithm of the
mrow element is used to produce a
math content box. That math content box is used as the content for the layout of
the element, as described by CSS for display: block
(if the computed value is block math) or
display: inline
(if the computed value is inline math).
Additionally, if the computed
display property is equal to
block math then that math content box is rendered
horizontally centered within the content box.
Note
TEX's display mode $$...$$
and inline mode $...$ correspond to
display="block" and display="inline"
respectively.
In the following example, a math formula
is rendered in display mode on a new line and taking full width,
with the math content centered within the container:
<div style="width: 15em;">
This mathematical formula with a big summation and the number pi
<math display="block" style="border: 1px dotted black;">
<mrow>
<munderover>
<mo>∑</mo>
<mrow><mi>n</mi><mo>=</mo><mn>1</mn></mrow>
<mrow><mo>+</mo><mn>∞</mn></mrow>
</munderover>
<mfrac>
<mn>1</mn>
<msup><mi>n</mi><mn>2</mn></msup>
</mfrac>
</mrow>
<mo>=</mo>
<mfrac>
<msup><mi>π</mi><mn>2</mn></msup>
<mn>6</mn>
</mfrac>
</math>
is easy to prove.
</div>
As a comparison, the same formula would look as follows in
inline mode. The formula is embedded in the paragraph of text
without forced line breaking.
The baselines specified by the layout algorithm of the
mrow are used for vertical
alignment. Note that
the middle of sum and equal symbols or fractions are all aligned,
but not with the alphabetical baseline of the surrounding
text.
Because good mathematical rendering requires use of mathematical
fonts, the
user agent stylesheet
should set the
font-family
to the
math
value on the <math> element instead of inheriting
it. Additionally, several CSS properties that can be set on
a parent container such as
font-style, font-weight,
direction or text-indent etc
are not expected to apply to the math formula and so the
user agent stylesheet
has rules to reset them by default.
math {
direction: ltr;
text-indent: 0;
letter-spacing: normal;
line-height: normal;
word-spacing: normal;
font-family: math;
font-size: inherit;
font-style: normal;
font-weight: normal;
display: inline math;
math-shift: normal;
math-style: compact;
math-depth: 0;
}
math[display="block" i] {
display: block math;
math-style: normal;
}
math[display="inline" i] {
display: inline math;
math-style: compact;
}
In addition to CSS data types, some MathML attributes rely on the following MathML-specific types:
- unsigned-integer
- An
<integer> value as defined in
[CSS-VALUES-4], whose first character is neither
U+002D HYPHEN-MINUS character (-) nor
U+002B PLUS SIGN (+).
- boolean
- A string that is an
ASCII case-insensitive
match to
true or
false.
The following attributes are common to and may be specified on all MathML
elements:
The
id,
class,
style,
data-*,
autofocus and
nonce and
tabindex
attributes have the same syntax and semantics as defined for
id,
class,
style,
data-*,
autofocus,
nonce and
tabindex
attributes on HTML elements.
The
dir
attribute, if present,
must be an
ASCII case-insensitive match
to ltr or rtl.
In that case, the user agent is expected to treat the attribute as a
presentational hint setting the element's
direction
property to the corresponding value.
More precisely, an
ASCII case-insensitive match
to rtl is mapped to rtl while
an ASCII case-insensitive match to ltr is mapped to ltr.
Note
The
dir attribute is used to set the directionality of math
formulas, which is often
rtl in Arabic speaking world.
However, languages written from right to left often embed math
written from left to right and so the
user agent stylesheet resets
the
direction
property accordingly on the
math
elements.
In the following example, the dir attribute
is used to render "𞸎 plus 𞸑 raised to the power of
(٢ over, 𞸟 plus ١)" from right-to-left.
<math dir="rtl">
<mrow>
<mi>𞸎</mi>
<mo>+</mo>
<msup>
<mi>𞸑</mi>
<mfrac>
<mn>٢</mn>
<mrow>
<mi>𞸟</mi>
<mo>+</mo>
<mn>١</mn>
</mrow>
</mfrac>
</msup>
</mrow>
</math>
All MathML elements support event handler content attributes,
as described in event handler content attributes in HTML.
All event handler content attributes
noted by HTML as being supported by all HTMLElements
are supported by all MathML elements as well, as defined in the MathMLElement IDL.
The
mathcolor
and
mathbackground
attributes, if present, must
have a value that is a
<color>.
In that case, the user agent is expected to treat these attributes as a
presentational hint setting the element's
color and
background-color
properties to the corresponding values.
The mathcolor attribute describes the foreground fill
color of MathML text, bars etc
while the mathbackground
attribute describes the background color of an element.
The
mathsize
attribute, if present, must
have a value that is a valid <length-percentage>.
In that case, the user agent is expected to treat the attribute as a
presentational hint setting the element's
font-size
property to the corresponding value.
The mathsize property indicates the desired height
of glyphs in math formulas but also scales other parts (spacing, shifts,
line thickness of bars etc) accordingly.
Note
The above attributes are implemented for compatibility with full MathML. Authors whose only target is MathML Core are encouraged to use CSS for styling.
The
displaystyle
attribute, if present, must have a value that is a boolean.
In that case, the user agent is expected to treat the attribute as a
presentational hint setting the element's
math-style
property to the corresponding value.
More precisely, an
ASCII case-insensitive match
to true is mapped to normal while
an ASCII case-insensitive match to false is mapped to compact.
This attribute indicates whether formulas should try to minimize
the logical height (value is false) or not
(value is true) e.g. by changing the size of content or
the layout of scripts.
The
scriptlevel
attribute, if present, must have value
+<U>, -<U> or <U>
where <U> is an
unsigned-integer.
In that case
the user agent is expected to treat the scriptlevel
attribute as a
presentational hint setting the element's
math-depth
property to the corresponding value.
More precisely,
+<U>, -<U> and
<U>
are respectively mapped to
add(<U>)
add(<-U>)
and <U>.
displaystyle and scriptlevel values
are automatically adjusted within MathML elements.
To fully implement these attributes, additional CSS properties must be
specified in the user agent stylesheet
as described in A. User Agent Stylesheet.
In particular, for all MathML elements a default
font-size: math is specified to ensure that
scriptlevel changes are taken into account.
In this example, an munder
element is used to attach a
script "A" to a base "∑". By default, the summation
symbol is rendered with the font-size inherited from its
parent and the A as a scaled down subscript.
If displaystyle is true, the summation symbol is drawn
bigger and the "A" becomes an underscript.
If scriptlevel is reset to 0 on the "A", then it will
use the same font-size as the top-level math root.
<math>
<munder>
<mo>∑</mo>
<mi>A</mi>
</munder>
<munder displaystyle="true">
<mo>∑</mo>
<mi>A</mi>
</munder>
<munder>
<mo>∑</mo>
<mi scriptlevel="0">A</mi>
</munder>
</math>
Note
T
EX's
\displaystyle,
\textstyle,
\scriptstyle, and
\scriptscriptstyle correspond
to
displaystyle and
scriptlevel as
true and
0,
false and
0,
false and
1,
and
false and 2, respectively.
The attributes
intent and arg
are reserved as valid attributes.
This specification does not define any observable behavior that is
specific to the intent and arg attributes.
Note
These attributes are described in [
MATHML4] and
future versions of this specification may or may not
define them. Authors should be aware that they are currently
in development and subject to change.
