javascriptieff自动添加事件

<script type="text/javascript">
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];
}

var Button1 = document.getElementById("Button1");
var Button1Click = function() { alert(1); };
addEventHandler(Button1, "click",  Button1Click);
addEventHandler(Button1, "click", function() { alert(2); } );
addEventHandler(Button1, "click", function() { alert(3); } );

//removeEventHandler(Button1, "click", function() { alert(2); } );
//removeEventHandler(Button1, "click", Button1Click);
</script>