Function on

static/js/codemirror/codemirror.js:4848–4858

(emitter, type, f)

  // EVENT HANDLING

  function on(emitter, type, f) {
    if (emitter.addEventListener)
      emitter.addEventListener(type, f, false);
    else if (emitter.attachEvent)
      emitter.attachEvent("on" + type, f);
    else {
      var map = emitter._handlers || (emitter._handlers = {});
      var arr = map[type] || (map[type] = []);
      arr.push(f);
    }
  }

  function off(emitter, type, f) {
    if (emitter.removeEventListener)