code: function forEachEventType(eventTypes, handler, callback, thisValue) {
  
  		var i,
  			type;
  
  		for (i = 0; i < eventTypes.length; i++) {
  			type = eventTypes[i];
  
  			// only call the callback if the event is on the handler
  			if (handler['on' + type]) {
  				callback.call(thisValue, type);
  			}
  		}
  	}
docs: Iterates over each supported event type that is also in the handler, applying
  a callback function. This is used to more easily attach/detach all events.
  @param {string[]} eventTypes A list of event types to iterate over
  @param {Object} handler An object with onclick, onmouseover, etc. methods.
  @param {Function} callback The function to call on each event type.
  @param {Object} [thisValue] The value of "this" inside the callback.
  @returns {void}
  @private