<script type="text/javascript">
function ShowSub(li) {//函数定义
var subMenu = li.getElementsByTagName("ul")[0] ;//获取
subMenu.style.display = " block ";
}
function HideSub(li) {
var subMenu = li.getElementsByTagName("ul")[0];
subMenu.style.display = " none ";
}
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*{ margin:0px; padding:0px;}
body{ font-family:Verdana, Geneva, sans-serif; font-size:14px;}
#nav{ width:600px; height:40px; background-color:#eee; margin:0 auto;}
ul{ list-style:none;}
ul li{ float:left; line-height:40px; text-align:center; width:100px;}//ie7显示宽度的兼容性 设置width 而不用padding的自适应
a{ text-decoration:none; color:#000; display:block;}
a:hover{ color:#F00; background-color:#666;}
ul li ul li{ float:none;background-color:#eee; margin:2px 0px;}
ul li ul{ display:none;}

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