mathjax.js

This repository contains some scripts to load MathJax conditionally in order to use it as a MathML polyfill. This is done by performing MathML feature detections. You just need to insert one line in your document header:

<html>
  <head>
    ...
    <script src="https://fred-wang.github.io/mathjax.js/mpadded-min.js"></script>
    ...
  </head>
  ...
</html>

This will load MathJax for browsers that do not implement the <mpadded> element (at the moment all but Gecko browsers). Replace mpadded with mspace if you wish to verify support for the <mspace> element instead (which is also supported in recent versions of WebKit).

Note however that MathJax is a heavy Javascript library, so in some situations you might prefer a small mathml.css stylesheet with only limited constructions for basic mathematics.

You might also consider the mathml-warning script, which displays a warning message and let the user choose one of the MathML polyfill.