本文实例讲述了js+css实现导航效果的方法。分享给大家供大家参考。具体实现方法如下：

1. 程序代码如下：

CSS+JS实现兼容性很好的无限级下拉菜单

*{ margin:0; padding:0; border:0;}

body{font:12px/130% verdana,geneva,arial,helvetica,sans-serif,宋体;}li{list-style:none;}

.clearfix:after{content:" ";display:block;height:0;clear:both;visibility:hidden;}.clearfix{display:inline-block;}

a:link{ color:#000; text-decoration:none; }

a:visited{ color:#000; text-decoration:none; }

a:hover{ color:#000; text-decoration:none; }

.menu{ width:778px; height:26px; background:#fff; margin:0 auto;}

.menusel{ float:left;width:100px; position:relative; height:25px; background:#ddd; line-height: 25px; margin-left: 1px; *margin-left: 0px;_margin-left: -1px;}

.menusel h2{ font-size:12px; }

.menusel a{ display: block;text-align:center; width:100px;border:1px solid #a4a4a4; height:25px; border-bottom:1px solid #a4a4a4; position:relative; z-index:2;}

.menusel a:hover{ border:1px solid #a4a4a4; border-bottom:1px dashed #eeeeee; position:relative; z-index:2; height:25px;}

.ahover a{border-bottom:1px dashed #eeeeee; background:#eeeeee; }

.position{ position:absolute; z-index:1;}

.menusel ul{width:125px; background:#eee; border:1px solid #a4a4a4; margin-top: -1px; position:relative; z-index:1; display:none;}

.menusel .block{ display:block;}

.typeul li{border-bottom:1px dashed #a4a4a4;width:125px; position:relative; float:left; }

.typeul li a{ border:none;width:125px; }

.typeul li a:hover{ border:none; background:#ddd;}

.typeul{  margin-left:0;  }

.typeul ul{left:125px; top:0; position:absolute;}

.fli{ margin-left: -1px; border-left:#eeeeee solid 1px;}

.menusel .lli{ border:none; }

for(var x = 1; x < 4; x++)

{

var menuid = document.getElementById("menu"+x);

menuid.num = x;

type();

}

function type()

{

var menuh2 = menuid.getElementsByTagName("h2");

var menuul = menuid.getElementsByTagName("ul");

var menuli = menuul[0].getElementsByTagName("li");

menuh2[0].onmouseover = show;

menuh2[0].onmouseout = unshow;

menuul[0].onmouseover = show;

menuul[0].onmouseout = unshow;

function show()

{

menuul[0].className = "clearfix typeul block"

}

function unshow()

{

menuul[0].className = "typeul"

}

for(var i = 0; i < menuli.length; i++)

{

menuli[i].num = i;

var liul = menuli[i].getElementsByTagName("ul")[0];

if(liul)

{

typeshow()

}

}

function typeshow()

{

menuli[i].onmouseover = showul;

menuli[i].onmouseout = unshowul;

}

function showul()

{

menuli[this.num].getElementsByTagName("ul")[0].className = "block";

}

function unshowul()

{

menuli[this.num].getElementsByTagName("ul")[0].className = "";

}

}

2. 程序效果

希望本文所述对大家的javascript程序设计有所帮助。