JavaScript实现点击外部隐藏的下拉菜单

完整代码示例与运行环境

<!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=gb2312" /> <title>下拉菜单</title> <style type="text/css"> body{margin:20px auto;font-family:Arial, Helvetica, sans-serif;font-size:12px;width:950px;height:400px;border:solid 1px #aaa; position:relative;padding:10px;} ul{margin:0;padding:0;list-style:none;} .dropDownList{position:absolute;left:100px;top:100px;} /* .dropDownList div.dropdown select{display:none;}*/ .dropDownList div.dropdown{float:left;margin-right:50px;width:200px;} .dropDownList span{display:block;width:146px;height:26px;background:url(http://3.bp.blogspot.com/_bdBPvgEipxw/SRMUkLCdX0I/AAAAAAAAAP8/HgDXLapwpAw/s320/select.gif) left top no-repeat;line-height:26px;text-indent:12px;border:solid 1px #83BBD9;cursor:default;} .dropDownList span.over{background-position:left bottom;border-color:#B4C91A;}     .dropDownList ul{background:#eee;width:200px;display:none;}         .dropDownList ul li{height:20px;width:100%;padding:3px 0;text-indent:12px;cursor:default;}         .dropDownList ul li.over{background:#ccc;}     .dropDownList ul.show{display:block;} </style> </head> <body> <h1>JavaScript模拟下拉菜单，做的仓促，虚心接受批评。</h1>  </body> </html> 

[Ctrl+A 全选 注:引入外部Js需再刷新一下页面才能执行]