MathML Attribute Values

In addition to CSS data types, some MathML attributes accept the following types:

• <unsigned-integer>: An <integer>, whose first character is neither U+002D HYPHEN-MINUS character (-) nor U+002B PLUS SIGN (+); for example 1234.
• <boolean>: A string true or false representing a boolean value.

Instead of <length-percentage>, MathML used to define its own type to describe lengths. Accepted values included non-zero unitless length values (e.g. 5 to mean 500%), values containing numbers ending with a dot (e.g. 34.px), or named spaces (e.g. thinmathspace). For compatibility reasons, it is recommended to replace non-zero unitless length values with equivalent <percentage> values, to remove unnecessary dots in numbers, and to use the following replacement for named lengths:

veryverythinmathspace  => 0.05555555555555555em
verythinmathspace      => 0.1111111111111111em
thinmathspace          => 0.16666666666666666em
mediummathspace        => 0.2222222222222222em
thickmathspace         => 0.2777777777777778em
verythickmathspace     => 0.3333333333333333em
veryverythickmathspace => 0.3888888888888889em