一个css和js结合的下拉菜单，支持主流浏览器

<style>

a:link{color:white;text-decoration:none;}

a:visited{color:white;text-decorative:none;}

a:hover{color:white;text-decorative:none;}

a:active{color:white;text-decorative:none;}

li{float:left;display:inline;background-color:#003366;width:120px;text-align:center;margin:2px;padding:10px 0 5px 0;position:relative;}

.limouseover{background-color:#0033ff;color:red;}

.limouseout{background-color:#003366;color:black;}

li ul{display:none;width:120px;position:absolute;left:0;top:30px;}

li ul li{margin:0px auto;border-top:1px solid #006699;}



</style>

<ul id=menu1>

<li><a href="">首页</a></li>

<li><a href="">菜单1菜单1</a>

<ul>

<li><a href="">子菜单1子菜单1子菜单1子菜单1</a></li>

<li><a href="">子菜单2</a></li>

</ul>

</li>

<li><a href="">菜单2</a>

<ul>

<li><a href="">子菜单1子菜单1子菜单1子菜单1</a></li>

<li><a href="">子菜单2</a></li>

</ul>

</li>

</ul>



<script language=javascript>

function menu(menu1){

//鼠标移入移出classname切换和子菜单隐藏、显示切换。

if (document.getElementById(menu1)){

var menu_ul=document.getElementById(menu1);

if (menu_ul.getElementsByTagName("li").length){

var menu_li=menu_ul.getElementsByTagName("li");

for (i in menu_li){

menu_li[i].onmouseover=function(){this.className="limouseover";if (this.getElementsByTagName("ul").length){this.getElementsByTagName("ul")[0].style.display="block";}}

menu_li[i].onmouseout=function(){this.className="limouseout";if (this.getElementsByTagName("ul").length){this.getElementsByTagName("ul")[0].style.display="none";}}

}

}

}

}



</script>

<script>var menu1=new menu("menu1");</script>