listener = function(e) {
      if (fn(e) === false) {
        for (var i = 0; i < elements.length; ++i) {
          elements[i].removeEventListener(eventName, listener);
        }
      }
    }
Handles every event in this sequence.

@param {function(Event):*} fn The function to call on each event in the
    sequence. Return false from the function to stop handling the events.