<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.8.2.js"></script>
</head>
<style type="text/css">
.main{500px;height:400px;border:dashed 1px #ccc;margin:0 auto;line-height:400px;text-align:center;}
</style>
<body>
<script type="text/javascript">
$(function(){
$(".main").mouseover(function(){
setTimeout(function(){
alert('当你的鼠标移动到框体时，我会延迟3秒才显示哦！');
},3000)
});
})
</script>
<div class="main">把鼠标移入此框体中，等待3秒。</div>
</body>
</html>