Function _on

lib/FileAPI.core.js:110–135

(el, type, fn)

		 * Add event listener
		 */
		_on = function (el, type, fn){
			if( el ){
				var uid = api.uid(el);

				if( !_elEvents[uid] ){
					_elEvents[uid] = {};
				}

				var isFileReader = (FileReader && el) && (el instanceof FileReader);
				_each(type.split(/\s+/), function (type){
					if( jQuery && !isFileReader){
						jQuery.event.add(el, type, fn);
					} else {
						if( !_elEvents[uid][type] ){
							_elEvents[uid][type] = [];
						}

						_elEvents[uid][type].push(fn);

						if( el.addEventListener ){ el.addEventListener(type, fn, false); }
						else if( el.attachEvent ){ el.attachEvent('on'+type, fn); }
						else { el['on'+type] = fn; }
					}
				});
			}
		},


		/**