//绑定事件function addEvent(obj, type, fn) {    if(typeof obj.addEventListener != 'undefined') {        obj.addEventListener(type, fn, false);    } else {        //创建一个存放事件的哈希表        if(!obj.events) obj.events = {};        //第一次执行时执行        if(!obj.events[type]) {            //创建一个存放事件处理函数的数组            obj.events[type] = [];            //把第一次的事件处理函数先存储到第一个位置上            if(obj['on' + type]) obj.events[type][0] = fn;        }else{            //同一个注册函数进行屏蔽，不添加到计数器中            if(addEvent.equal(obj.events[type], fn)) return false;        }        //从第二次开始我们用事件计数器来存储        obj.events[type][addEvent.ID++] = fn;        //执行事件处理函数        obj['on' + type] = addEvent.exec;    }}addEvent.ID = 1;//执行事件处理函数addEvent.exec = function(event) {    var e = event || addEvent.fixEvent(window.event);    var es = this.events[e.type];    for(var i in es) {        es[i].call(this, e);    }}//同一个注册函数进行屏蔽addEvent.equal = function(es, fn) {    for(var i in es){        if(es[i] == fn) return true;    }    return false;}//把IE常用的Event对象配对到W3C中addEvent.fixEvent = function(event) {    event.preventDefault = addEvent.fixEvent.preventDefault;    event.stopPropagation = addEvent.fixEvent.stopPropagation;    return event;};//IE阻止默认行为addEvent.fixEvent.preventDefault = function() {    this.returnValue = false;}//IE取消冒泡addEvent.fixEvent.stopPropagation = function() {    this.cancelBubble = true;}//移除事件function removeEvent(obj, type, fn) {    if(typeof obj.removeEventListener != 'undefined') {        obj.removeEventListener(type, fn);    }else {        for(var i in obj.events[type]) {            if(obj.events[type][i] == fn) {                delete obj.events[type][i];            }        }    }}