事件监听函数添加与消除

function addEventHandler(target, type, func) {
    if (target.addEventListener)
        target.addEventListener(type, func, false);
    else if (target.attachEvent)
        target.attachEvent("on" + type, func);
    else target["on" + type] = func;
}
function removeEventHandler(target, type, func) {
    if (target.removeEventListener)
        target.removeEventListener(type, func, false);
    else if (target.detachEvent)
        target.detachEvent("on" + type, func);
    else delete target["on" + type];
}

 案例：

var Button1 = document.getElementById("Button1");
var test1 = function() { alert(1); };
function test2() {alert("2")}
addEventHandler(Button1,"click",test1);
addEventHandler(Button1,"click",test2 );
addEventHandler(Button1,"click", function() { alert("3"); } );
addEventHandler(Button1,"click", function() { alert("4"); } );
removeEventHandler(Button1,"click",test1);
removeEventHandler(Button1,"click",test2);
removeEventHandler(Button1,"click",function() { alert("3"); });

JavaScript的监听事件函数attachEvent和addEventListener使用方法

attachEvent方法，为某一事件附加其它的处理事件。（不支持Mozilla系列，用于IE8及以下版本）
addEventListener方法 用于 Mozilla系列及IE8以上IE内核浏览器。