12 March 2019
Remove debugging statements.
Fix syntax error.
See if MathJax can typeset detached elements.
Wait for MathJax before typesetting.
Get element from $content.
Use MutationObserver to detect when $content is added to the DOM.
Don't use $content as there are errors in MathJax using it (TypeError: c.nodeName is undefined).
Wait for $content to be added to page.
Use $content as #wikiPreview is not available when hook is fired.
Wait for MathJax; debugging.
Actually call callback to render MathJax.
Using $content doesn't seem to work.
Enable MathJax typesetting on edit preview pages.