MathJax Broken

[damianc]

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I noticed that MathJax does not work properly, i.e. fonts are not printed as expected (blackboard, fraktur, etc.) + binomial is broken. The mentioned things had worked and looked properly beforehands, and files was not modified since then.

Screens are from:

• https://github.com/damianc/math-notes/blob/master/mathjax/text.md
• https://github.com/damianc/math-notes/blob/master/algebra/pascals-triangle.md

EDIT
\cancel also is broken

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[jinohkang-theori]

As far as I'm aware, GitHub has recently (about a month ago) switched from CommonHTML to MathML rendering. MathJax v3's MathML output is based on the MathML3 specification.

The problem is that, as of August 2024, Chrome does not support MathML3.¹ Specifically, Chromium only claims to be conformant to the MathML-Core specification, which notably omits mathvariant attribute values other than mathvariant="normal".² This can be confirmed by looking at Chromium's user agent stylesheet for MathML (https://chromium.googlesource.com/chromium/src/+/main/third_party/blink/renderer/core/css/mathml.css); note missing rules for *[mathvariant=...].

GitHub could work around this issue by explicitly adding custom CSS rules for mi[mathvariant=...]. Yet another option is to revert to old MathJax CommonHTML rendering, but its security impact should be considered carefully in light of a recent XSS vulnerability discovered on GitHub caused by a MathJax issue.

Footnotes

1. See https://issues.chromium.org/issues/40947312. Meanwhile, some browsers (such as Firefox) do seem to respect mathvariant according to the same issue report. ↩

2. From MathML Core §3.2.2 Identifier <mi>: "The mathvariant attribute, if present, must be an ASCII case-insensitive match of normal." ↩

[jinohkang-theori]

Client-side workaround:

1. Remove data-mathml-enabled="true" attributes from math-renderer elements before the MathML rendering kicks in.
2. Use a custom CSS rule to complement Chrome's MathML support (at the cost of imperfect rendering).

[haimingz]

I am having the same problem here. It looks horrible!