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.

extendSelection(cm.doc, Pos(line, 0), clipPos(cm.doc, Pos(line + 1, 0)));
  }
  
  
  
  CodeMirror.prototype = {
    constructor: CodeMirror,
    focus: function(){window.focus(); focusInput(this); fastPoll(this);},
    setOption: function(option, value) {
      var options = this.options, old = options[option];
      if (options[option] == value && option != "mode") return;
      options[option] = value;
      if (optionHandlers.hasOwnProperty(option))
        operation(this, optionHandlers[option])(this, value, old);
    },
    getOption: function(option) {return this.options[option];},
    getDoc: function() {return this.doc;},
    addKeyMap: function(map, bottom) {
      this.state.keyMaps[bottom ? "push" : "unshift"](map);
    },
    removeKeyMap: function(map) {
      var maps = this.state.keyMaps;
      for (var i = 0; i < maps.length; ++i)
        if (maps[i] == map || (typeof maps[i] != "string" && maps[i].name == map)) {
          maps.splice(i, 1);
          return true;
        }
    },
    addOverlay: operation(null, function(spec, options) {
      var mode = spec.token ? spec : CodeMirror.getMode(this.options, spec);