Right now we use codemirror's JavaScript mode on the website but there's a JSX mode now so we should start using that instead.

if (textarea.form) {
      on(textarea.form, "submit", save);
      
      if (!options.leaveSubmitMethodAlone) {
        var form = textarea.form, realSubmit = form.submit;
        try {
          var wrappedSubmit = form.submit = function() {
            save();
            form.submit = realSubmit;
            form.submit();
            form.submit = wrappedSubmit;
          };
        } catch(e) {}
      }
    }
    textarea.style.display = "none";
    var cm = CodeMirror(function(node) {
      textarea.parentNode.insertBefore(node, textarea.nextSibling);
    }, options);
    cm.save = save;