我的代碼有什么問題，為什么點擊后不能彈出提示信息
<!DOCTYPE htmL>
<html>
<head>
??? <meta charset="utf-8">
?<title></title>
</head>
<body>
? <div>
??? <input type="button" value="確定"? id="btn1">
? </div>
<script type="text/javascript">
?function showmes(){
??alert('hello world!');
?}
??? var btn1=document.getElementById("btn1");
??? var eventUtil ={
??? ?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;
??? ??}
??? ?}
??? }
??? eventUtil.addHandler(btn1,'click',showmes);
</script>
</body>
</html>
2016-08-11
?else if(element.attachEvent{
????????????? element.attachEvent('on'+type,handler)；
??? ??}
少了一個反括號，而且分號不是英文的
2016-08-11
如圖所示，多多練習(xí)。