封装兼容性添加、删除事件的函数 addEventListener与removeEventListener

var Event = {
    addHandler: function (oElement, sEvent, fnHandler) {
        oElement.addEventListener ? oElement.addEventListener(sEvent, fnHandler, false) : oElement.attachEvent("on" + sEvent, fnHandler)
    },
    removeHandler: function (oElement, sEvent, fnHandler) {
        oElement.removeEventListener ? oElement.removeEventListener(sEvent, fnHandler, false) : oElement.detachEvent("on" + sEvent, fnHandler)
    }
}
window.onload = function ()
{
    var aBtn = document.getElementsByTagName("input");

    //为第一个按钮添加绑定事件
    aBtn[1].onclick = function ()
    {
        Event.addHandler(aBtn[0], "click", fnHandler);
        aBtn[0].value = "我可以点击了"
    }

    //解除第一个按钮的绑定事件
    aBtn[2].onclick = function ()
    {
        Event.removeHandler(aBtn[0], "click", fnHandler);
        aBtn[0].value = "毫无用处的按钮"
    }

    //事件处理函数
    function fnHandler ()
    {
        alert("事件绑定成功！")
    }
}

<input type="button" value="毫无用处的按钮"> <input type="button" value="绑定click"> <input type="button" value="解除绑定">