MediaWiki:Common.js

/* Any JavaScript here will be loaded for all users on every page load. */

mw.hook('wikipage.content').add(function ($content) {
  console.log($content);
  console.log(typeof $content);
  var observer = new MutationObserver(function(mutations) {
    if (document.contains($content)) {
      console.log("It's in the DOM!");
      // using $content directly throws errors
      MathJax.Hub.Queue(["Typeset", MathJax.Hub, document.getElementById("wikiPreview")]).execute();
      observer.disconnect();
    } else {
      console.log("Still waiting");
    }
  });
  observer.observe(document, {attributes: false, childList: true, characterData: false, subtree: true});
});