js鼠标经过显示二级下拉菜单效果代码

提示：您可以先修改部分代码再运行

<!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=utf-8" />
<title>setTimeout应用</title>
<style>
body,div,ul,li,p{margin:0;padding:0;}
body{font:12px/1.5 Arial;}
ul{list-style-type:none;}
#nav,#nav ul,#nav ul li,#nav ul li a:hover,#nav .subnav,#nav .subnav p,#nav .subnav p span,#nav .subnav .arrow{background:url(img/nav_bg.png) no-repeat;}
#nav{position:relative;width:910px;background-position:0 -36px;margin:10px auto;}
#nav ul{height:36px;line-height:36px;margin-left:10px;padding-right:10px;overflow:hidden;background-position:right -72px;}
#nav ul li{float:left;width:110px;margin-left:-2px;background-position:0 -108px;}
#nav ul li a{font-size:14px;color:#fff;width:102px;display:block;text-align:center;text-decoration:none;margin:0 2px 0 4px;}
#nav ul li a:hover{font-weight:700;background-position:-3px -144px;}
#nav .subnav{display:none;position:absolute;top:41px;width:auto!important;min-width:110px;height:27px;line-height:27px;white-space:nowrap;background-position:0 -180px;}
#nav .subnav p{margin-left:10px;padding-right:10px;background-position:right -234px;}
#nav .subnav p span{display:block;color:#235e99;background-repeat:repeat-x;background-position:0 -207px;}
#nav .subnav p a{font-size:12px;display:inline;color:#235e99;text-decoration:none;margin:0 5px;padding:0 2px;}
#nav .subnav p a:hover{font-weight:400;background-image:none;border-bottom:2px solid;}
#nav .subnav .arrow{position:absolute;top:-4px;display:block;width:11px;height:5px;background-position:0 -261px;}
</style>
<script type="text/javascript">
var get = {
	byId: function(id) {
		return document.getElementById(id)
	},
	byClass: function(sClass, oParent) {
		var aClass = [];
		var reClass = new RegExp("(^| )" + sClass + "( |$)");
		var aElem = this.byTagName("*", oParent);
		for (var I = 0; I < aElem.length; i++) reClass.test(aElem[i].className) && aClass.push(aElem[i]);
		return aClass
	},
	byTagName: function(elem, obj) {
		return (obj || document).getElementsByTagName(elem)
	}
};
window.onload = function ()
{
	var oNav = get.byId("nav");
	var aLi = get.byTagName("li", oNav);
	var aSubNav = get.byClass("subnav", oNav);
	var oSubNav = oEm = timer = null;
	var I = 0;
	
	for (I = 1; I < aLi.length; i++)
	{
		aLi[i].onmouseover = function ()
		{
			//隐藏所有子菜单
			for (I = 0; I < aSubNav.length; i++)aSubNav[i].style.display = "none";
			
			//获取该项下的子菜单
			oSubNav = get.byClass("subnav", this)[0];
			
			//获取该项下的指示箭头
			oEm = get.byTagName("em", this)[0];
			
			//显示该项下的子菜单
			oSubNav.style.display = "block";
			
			//判断显示区域
			oNav.offsetWidth - this.offsetLeft > oSubNav.offsetWidth ? 
			
			//如果在显示范围居左显示
			oSubNav.style.left = this.offsetLeft + "px" :
			
			//超出显示范围居右显示
			oSubNav.style.right = 0;
			
			//计算指标箭头显示位置
			oEm.style.left = this.offsetLeft - oSubNav.offsetLeft + 50 + "px";
			clearTimeout(timer);
			
			//阻止事件冒泡
			oSubNav.onmouseover = function (event)
			{
				(event || window.event).cancelBubble = true;
				clearTimeout(timer)
			}
		};
		
		aLi[i].onmouseout = function ()
		{
			timer = setTimeout(function () {
				oSubNav.style.display = "none"
			},300)	
		}
	}
};
</script>
</head>
<body>
<div id="nav">
    <ul>
        <li>站长之家</li>
        <li>
            行业资讯
            <div class="subnav">
                <em class="arrow"></em>
                <p>        	
                    <span>
                        业界动态|
                        收购融资|
                        门户动态|
                        搜索引擎|
                        网络游戏|
                        电子商务|
                        广告传媒|
                        厂商开发
                    </span>
                </p>
            </div>
        </li>
        <li>
            站长在线
            <div class="subnav">
                <em class="arrow"></em>
                <p>        	
                    <span>
                        站长报道|
                        好站推荐|
                        站长聚会|
                        站长访谈|
                        站长茶馆|
                        网站排行
                    </span>
                </p>
            </div>
        </li>
        <li>
            网站运营
            <div class="subnav">
                <em class="arrow"></em>
                <p>        	
                    <span>
                        建站经验|
                        策划盈利|
                        搜索优化|
                        网站推广|
                        免费资源
                    </span>
                </p>
            </div>
        </li>
        <li>
            设计在线
            <div class="subnav">
                <em class="arrow"></em>
                <p>        	
                    <span>
                        酷站推荐|
                        网页设计|
                        WEB标准|
                        视频处理|
                        设计活动
                    </span>
                </p>
            </div>
        </li>
        <li>
            网络编程
            <div class="subnav">
                <em class="arrow"></em>
                <p>        	
                    <span>
                        Asp编程|
                        Php编程|
                        .Net编程|
                        Xml编程|
                        Access|
                        Mssql|
                        Mysql
                    </span>
                </p>
            </div>
        </li>
        <li>
            联盟资讯
            <div class="subnav">
                <em class="arrow"></em>
                <p>        	
                    <span>
                        联盟动态|
                        联盟介绍|
                        联盟点评|
                        网赚技巧
                    </span>
                </p>
            </div>
        </li>
        <li>
            服务器
            <div class="subnav">
                <em class="arrow"></em>
                <p>        	
                    <span>
                        Web服务器|
                        Ftp服务器|
                        Mail服务器|
                        Dns服务器|
                        Win服务器|
                        Linux服务器|
                        安全防护|
                        虚拟主机
                    </span>
                </p>
            </div>
        </li>        
    </ul>    
</div>
</body>
</html></td>
	  </tr>
	</table>

提示：您可以先修改部分代码再运行

补充：网页特效,导航菜单