JavaScript实现鼠标悬停链接弹出提示层

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>鼠标移到文字上弹出提示层</title>
<style type="text/css">
<!--
#box{
display:none;
width: 315px;
height: 180px; 
background:#CCC;
border:1px solid #333;
padding:12px;
text-align:center;
}
-->
</style>
<script type="text/javascript" language="javascript" >
<!--
function display(){
document.getElementById("box").style.display="block"; 
}
function disappear(){
document.getElementById("box").style.display="none"; 
}
-->
</script>
</head>
<body>
<a href="#" onmouseover="display()" onmouseout="disappear()">
鼠标放到这儿！
</a>
<div id="box" onmouseover="display()" onmouseout="disappear()">
效果不错吧？这里面你可以设置一张图片，也可以是一段文字，
而且源代码很简单哦！
</div>
</body>
</html>