為什么這個btn3無法運行
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div>
<input type="button" value="按鈕" id="btn" onclick="showMessage()">
<input type="button" value="按鈕2" id="btn2">
<input type="button" value="按鈕3" id="btn3">
</div>
<script>
function showMessage(){
alert('hello world!');
}
var btn2=document.getElementById('btn2');
var btn3=document.getElementById('btn3');
btn2.onclick=function(){
alert('這是通過Dom0觸發的事件！');
}
btn2.onclick=null;
var eventUtil={
//添加句柄
addHandler:function(element,type,handler){
if(element.addEventListener){
element.addEventListener(type,handler,false);
}else?
if(element.attachEvent){
element.attachEvent('on'+type,handler);
}
else{
element['on'+type]=handler;
}
},
//添加句柄
removeHandler:function(element,type,handler){
if(element.removeEventListener){
element.removeEventListener(type,handler,false);
}else if(element.detachEvent){
element.detachEvent('on'+type,handler);}
else{
element['on'+type]=null;
}
}
eventUtil.addHandler(btn3,'click',showMessage);
</script>
?
</body>
</html>
2015-12-22
<script> ????function?showMessage(){ ????????alert('hello?world!'); ????} ????var?btn2=document.getElementById('btn2'); ????var?btn3=document.getElementById('btn3'); ????btn2.onclick=function(){ ????????alert('這是通過Dom0觸發的事件！'); ????} ????btn2.onclick=null; ????var?eventUtil=?{ //添加句柄 ????????addHandler:?function?(element,?type,?handler)?{ ????????????if?(element.addEventListener)?{ ????????????????element.addEventListener(type,?handler,?false); ????????????}?else?if?(element.attachEvent)?{ ????????????????element.attachEvent('on'?+?type,?handler); ????????????} ????????????else?{ ????????????????element['on'?+?type]?=?handler; ????????????} ????????}, //添加句柄 ????????removeHandler:?function?(element,?type,?handler)?{ ????????????if?(element.removeEventListener)?{ ????????????????element.removeEventListener(type,?handler,?false); ????????????}?else?if?(element.detachEvent)?{ ????????????????element.detachEvent('on'?+?type,?handler); ????????????} ????????????else?{ ????????????????element['on'?+?type]?=?null; ????????????} ????????} ????}?//這里少一個?} ????eventUtil.addHandler(btn3,'click',showMessage); </script>2015-12-22
var eventUtil={ 少了個 結束的花括號 ｝