<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<style type="text/css">
*{margin: 0; padding: 0;font-family:arial;}
.messdiv{position: relative;width: 150px; height: auto;font-size: 14px;margin: 20px 0 0 20px;}
.selecshow{display: none;position: absolute;border: 1px solid #ccc; box-shadow: 0px 8px 16px 0px #666;padding: 10px;min-width: 140px;line-height: 30px;}
.messdiv:hover .selecshow{display: block;}
</style>
<body>
<div class="messdiv">
<span>鼠标划我显示下拉信息</span>
<div class="selecshow">
<p>下拉信息1</p>
<p>下拉信息2</p>
</div>
</div>
</body>
</html>
原文：http://www.cnblogs.com/dazhangli/p/5855746.html