IE8- 下, jQuery 绑定自定义事件之后, 无法删除导致内存泄露问题

remove-event.js

// jQuery 1.7.2- removeEvent 的代码
	function( elem, type, handle ) {
		if ( elem.detachEvent ) {
			elem.detachEvent( "on" + type, handle );
		}
	};
	
// jQuery 1.8.0+ removeEvent 的代码
	function( elem, type, handle ) {
		var name = "on" + type;

		if ( elem.detachEvent ) {

			// #8545, #7054, preventing memory leaks for custom events in IE6-8 –
			// detachEvent needed property on element, by name of that event, to properly expose it to GC
			if ( typeof elem[ name ] === "undefined" ) {
				elem[ name ] = null;
			}

			elem.detachEvent( name, handle );
		}
	};
	
	
// 相关 https://github.com/markelog/jquery/commit/71260802ab48e3926e56b5d2ff819e1a53d8217c
// - http://www.reigndropsfall.net/2011/01/05/internet-explorer-event-handler-leaks/