Add CSS class to math when using MathJax with HTML

[ewancarr]

Would it be possible to add a class (e.g. <p class="eq">) to the HTML output from MathJax equations, so they can be targeted with CSS selectors.

For example, the input

  $$e=mc^2$$

Would produce the HTML:

  <p class="eq">\[e=mc^2\]</p>

Currently, there is no class:

  <p>\[e=mc^2\]</p>