请问这样子为什么不能触发鼠标事件?
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>鼠标移开事件 </title>
<script type="text/javascript">
var name=document.getElementById("first");
name.onmouseout=function(){
alert("相信我,frighting");
}
</script>
</head>
<body>
<form id="first">
<a href="http://www.imooc.com">点击我</a>
</form>
</body>
</html>