js事件监听/鼠标滚轮/行为/冒泡/键盘的兼容性写法

addEvent:function(el,type,fn,capture) {
    if (window.addEventListener) {    
        if (type === "mousewheel" && document.mozHidden !== undefined) {
            type = "DOMMouseScroll";
        }    
        el.addEventListener(type, fn, !!capture);
    } else if (window.attachEvent) {
        el.attachEvent("on" + type, fn);
    }
},
removeEvent:function(el,type,fn,capture) {
    if (window.removeEventListener) {    
        if (type === "mousewheel" && document.mozHidden !== undefined) {
            type = "DOMMouseScroll";
        }    
        el.removeEventListener(type, fn, !!capture);
    } else if (window.detachEvent) {
        el.detachEvent("on" + type, fn);
    }
},
//对鼠标滚轮、行为、冒泡以及键盘做的兼容性处理
eventCompat:function(e) {
    e || (e = root.event);
    var type = e.type;
    if (type == 'DOMMouseScroll' || type == 'mousewheel') {
        e.delta = (e.wheelDelta) ? -e.wheelDelta / 120 : (e.detail || 0) / 3;
    }
    if (e.srcElement && !e.target) {
        e.target = e.srcElement;    
    }
    //阻止默认行为
    if (!e.preventDefault) {
        e.preventDefault = function() {
            e.returnValue = false;
        };
    }
    //阻止冒泡
    if (!e.stopPropagation && e.cancelBubble !== undefined) {
        e.stopPropagation = function() {
            e.cancelBubble = true;
        };
    }
    //键盘的兼容性处理
    if(e.which == null){
        e.which = e.charCode != null ? e.charCode : e.keyCode;
    }
    /* 
       ......其他一些兼容性处理 */
    return e;
},
bindAsEventListener:function(context, fun) {
    var self = this;
    return function(e) {
        return fun.call(context, self.eventCompat(e));
    }
}


//调用：
var dom = document.getElementById('btn');
var object = {
    clickCtrl:function(e){
        alert(e);    
    }
};

addEvent(dom, "click", function(){
    alert(dom.id);                                       
});

addEvent(dom, "mousedown", 
    bindAsEventListener(object, function(e){ 
        object.ClickCtrl(e);
}));