<!doctype html>
<html><head><meta charset="utf-8"><title>无标题文档</title><style>body,ul,li{ margin:0; padding:0;}.box{ width:400px; margin:50px auto;}.box li{ list-style:none; cursor:pointer;}.box ul{ float:left; width:100px; margin-right:10px; text-align:center; height:30px; line-height:30px; background:#999;}.box ul li ul{ display:none; width:100px; text-align:center; }.box li ul li{ background:#CCC; height:30px; line-height:30px;}</style></head><body><div class="box"> <ul> <li onMouseOver="document.getElementById('list_1').style.display='block';" onMouseOut="document.getElementById('list_1').style.display='none';"><a href="#" target="_blank">平面设计</a> <ul id="list_1"> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> </ul> </li> </ul> <ul> <li onMouseOver="document.getElementById('list_2').style.display='block';" onMouseOut="document.getElementById('list_2').style.display='none';"><a href="#" target="_blank">平面设计</a> <ul id="list_2"> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> </ul> </li> </ul> <ul> <li onMouseOver="document.getElementById('list_3').style.display='block';" onMouseOut="document.getElementById('list_3').style.display='none';"><a href="#" target="_blank">平面设计</a> <ul id="list_3"> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> <li><a href="#" target="_blank">平面设计</a></li> </ul> </li> </ul></div></body></html>