var countInner = 0;
var countOuter = 0;
var countMid = 0;
var addListener = function(el, type, handle){
    //在这里也是重新定义addListener方法
    countOuter++; //计算外部的函数将会执行多少次
    addListener = (function(){
        if (el.addEventListener) {
            countMid++; //计算if下将会执行多少次，下同
            return function(el, type, handle){
                countInner++; //计算内部的函数将会执行多少次，下同
                el.addEventListener(type, handle, false);
            };
        } else 
            if (el.attachEvent) {
                countMid++;
                return function(el, type, handle){
                    countInner++;
                    el.attachEvent("on" + type, function(e){
                        handle.call(el, e);
                    });
                };
            } else {
                countMid++;
                return function(el, type, handle){
                    countInner++;
                    el["on" + type] = handle;
                };
            }
    })();
    addListener(el, type, handle);
}

var benchmark = function(fn, times){
    var d1 = new Date(), d2, n;
    while (times--) 
        n = fn();
    var d2 = new Date();
    return d2.getTime() - d1.getTime();
}

alert(benchmark(function(){
    var rand = Math.random() * 100000;
    var div = document.createElement("div");
    div.id = "div" + rand;
    div.innerHTML = "div text" + rand;
    addListener(div, "click", function(e){
        alert(this.id);
    });
    document.body.appendChild(div);
    
}, 1000));
alert(countInner);
alert(countOuter);
alert(countMid);