Various legacy MathML features have been deprecated or removed

Published: | Categories: Miscellaneous


Firefox 70 has updated the MathML implementation in an effort to comply with the current MathML Core (future MathML 4) spec.

The following features are implemented in WebKit as well, but now are deprecated, disabled in Firefox Nightly and will be removed in the future:

  • Named values for the linethickness attribute on the <mfrac> element, including thin, medium and thick
  • Named values for the mathsize attribute on the <mtext> and other elements, including small, normal and big
  • Named length values including veryverythinmathspace, verythinmathspace, thinmathspace, mediummathspace, thickmathspace, verythickmathspace, veryverythickmathspace, negativeveryverythinmathspace, negativeverythinmathspace, negativethinmathspace, negativemediummathspace, negativethickmathspace, negativeverythickmathspace and negativeverythickmathspace. See this conversion if needed
  • Style attributes including background, color, fontfamily, fontsize, fontstyle and fontweight, which have been deprecated since Firefox 20. Use mathbackground, mathcolor, mathsize and mathvariant instead

The following features have been removed:

  • The mode attribute on the <math> element, which was implemented only in Firefox and deprecated since Firefox 20 in favour of the display attribute. A polyfill is available for legacy documents
  • Non-zero unitless length values, such as 5 for 500%, which have been deprecated since Firefox 20
  • Length values ending with a dot, such as 2. or 34.px