Use MathJax with Spectacle

### Question

I intend to use [ox-spectacle](https://github.com/lorniu/ox-spectacle) which is a backend for using `spectacle.js` within `emacs/orgmode`.

Everything works well except that math formula are not rendered by `MathJax`.

You can see that with the example [scratch.html](https://lorniu.github.io/spectacle/scratch.html) although
there is a call to `mathjax` script in the html source file.

I tried to make the script work, by making the `mathjax` script local and/or modifying its configuration, but nothing works.

I thought eventually you would notice bettter than I what the problem is ? or to the least could you provide a simple example with `mathjax` working ?

EDIT : the above linked file does work with `firefox` but not with `chrome`.

Regards