code: function(element, check, go) {
        var shouldAdd = element.__queue && !element.__queue.check;
        if (shouldAdd) {
          queueForElement(element).push(element);
          element.__queue.check = check;
          element.__queue.go = go;
        }
        return (this.indexOf(element) !== 0);
      }
docs: enqueue an element to the next spot in the queue.