当鼠标移出灰色区域时候,菜单项怎么隐藏起来_javascript技巧

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>无标题文档</title> <script language="javascript"> var $=function(id){ return document.getElementById(id); } function hover(){ if($('hover').style.display == 'none'){ $('hover').style.display = ''; }else{ $('hover').style.display = 'none'; } } </script> <style> *{margin:10px; padding:0} #nav{border:#ccc 1px solid; height:25px; width:198px; text-align:center; line-height:25px; margin-bottom:0} #hover{ position:absolute; height:100px; width:200px; margin-top:-2px; text-align:center; background-color:#ccc; } </style> <div id="nav" onmouseover="return hover();" onmouseout="return hover();"><a href="##">鼠标移上来</a></div> <div id="hover" style="display:none;" onmouseover="return hover();" onmouseout="return hover();"> <ul> <li><a href="javascript:void(null)">菜单一</a></li> <li> <a href="javascript:void(null)">菜单二</a> </li> </ul> </div>
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]