<!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>下拉列表 简单</title> <style type="text/css"> .xianshi { position: absolute; left: 0px; top: 160px; width: 213px; height: 44px; z-index: 2; line-height: 5px; border: solid 2px #0066FF; overflow:visible; } .yincang { position: absolute; left: 0px; top: 160px; width: 213px; height: 44px; z-index: 2; line-height: 5px; border: solid 2px #0066FF; overflow:hidden; } #apDiv8 { position: absolute; left: 213px; top: -2px; width: 270px; height: 355px; z-index: 3; border: solid 2px #0066FF; line-height: 25px; vertical-align: middle; } </style> </head> <body> <div id="apDiv1" align="center" class="yincang" onmouseover="this.className=‘xianshi‘" onmouseout="this.className=‘yincang‘"><h3>首页</h3> <div id="apDiv2">首页一</div> </div> </body> </html>
原文：http://www.cnblogs.com/zxm1002/p/5059307.html