不解釋，看代碼：

代碼如下:
;(function(){
    //進(jìn)行庫封裝，防止對(duì)象污染
    window['cm']={};
/**
    *給對(duì)象注冊(cè)事件
    */
    var addListener=function(element,type,fn){
        if(typeof element == 'undefined') return false;
        if(element.addEventListener){
            element.addEventListener(type,fn,false);
        }else if(element.attachEvent){
            //將事件緩沖到該標(biāo)簽上,已解決this指向window(現(xiàn)fn內(nèi)this指向element)和移除匿名事件問題
            var _EventRef='_'+type+'EventRef';
            if(!element[_EventRef]){
                element[_EventRef]=[];
            }
            var _EventRefs=element[_EventRef];
            var index;
            for(index in _EventRefs){
                if(_EventRefs[index]['realFn']==fn){
                    return;
                }
            }
            var nestFn=function(){
                fn.apply(element,arguments);
            };
            element[_EventRef].push({'realFn':fn,'nestFn':nestFn});
            element.attachEvent('on'+type,nestFn);
        }else{
            element['on'+type]=fn;
        }
    };
    window['cm']['addListener']=addListener;
    /**
    *移除對(duì)象上已注冊(cè)事件
    */
    var removeListener=function(element,type,fn){
        if(typeof element == 'undefined') return false;
        if(element.removeEventListener){