好像是不支持ff.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd" [ <!ELEMENT a (#PCDATA | table)* > ]>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" >
<head>
<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=UTF-8" />
<title>纯CSS下拉菜单,兼容IE和FF</title>
<style type="text/css">
body {color:#fff;}
#wrapper color:#000;}
.red {color:#c00;}
#info {margin-top:20px;}
#info h1 {font-size:3em; text-align:center; font-family: georgia, "times new roman", serif;}
#head {height:145px; border:0;}
#positioner {clear:both; position:relative; left:1px; z-index:100;}
#ads {position:relative; z-index:10;}
.menu {font-size:12px;position:relative;z-index:100;}
#noniemenu {position:absolute;}
#noniemenu .holder ul {padding:0; margin:0;}
#noniemenu .holder ul li {list-style-type: none;}
#noniemenu .holder li {}
#noniemenu .holder li ul {display: none;}
#noniemenu .holder li:hover > ul#a3 {display:block; position:absolute; left:105px; margin-top:-20px; border:1px solid #000;}
#noniemenu .holder .bold {font-weight:bold;}
#noniemenu .holder {
color:#fff;
width:104px;
height:18px;
display:block;
overflow:hidden;
float:left;
border:1px solid #000;
margin-right:1px;
font-size:10px;
}
#noniemenu .holder:hover {
height:auto;
}
#noniemenu a.outer, #noniemenu a.outer:visited {
color:#fff;
width:104px;
line-height:18px;
display:block;
background:#e09222;
text-align:center;
text-decoration:none;
font-family: verdana, arial, sans-serif;
}
#noniemenu a.outer:hover {
background:#697210;
overflow:visible;
}
#noniemenu div.open {display:none;}
#noniemenu a.inner, #noniemenu a.inner:visited {
display:block;
width:104px;
height:18px;
line-height:18px;
border-bottom:1px solid #000;
text-decoration:none;
color:#000;
background:#eee;
text-align:center;
}
#noniemenu a.second {font-weight:bold;}
#noniemenu a.inner:hover {
background:#add;
}
</style>
<!--[if lte IE 6]>
<style type="text/css">
body {margin-top:-8px;}
#head {height:147px;}
#noniemenu {display:none;}
.menu {display:block; position:absolute;}
.menu a.outer, .menu a.outer:visited {
color:#fff;
width:104px;
height:18px;
display:block;
background:#e09222;
border:1px solid #000;
margin-right:1px;
text-align:center;
float:left;
text-decoration:none;
font-family: verdana, arial, sans-serif;
font-size:10px;
line-height:18px;
overflow:hidden;
}
.menu a.outer:hover {
background:#697210;
overflow:visible;
}
.menu a.outer:hover table.first {
display:block;
background:#eee;
border-collapse:collapse;
}
.menu a.inner, .menu a.inner:visited {
display:block;
width:102px;
height:18px;
border-bottom:1px solid #000;
text-decoration:none;
color:#000;
font-family: verdana, arial, sans-serif;
font-size:10px;
text-align:center;
}
.menu a.inner:hover {
background:#add;
}
.menu a.outer table.first a.second {
height:18px;
line-height:18px;
overflow:hidden;
font-weight:bold;
}
.menu a.outer table.first a.second:hover {
position:relative;
overflow:visible;
}
.menu a.outer table.first a.second:hover table {
position:absolute;
top:-2px;
left:102px;
border-collapse:collapse;
background:#eee;
border:1px solid #000;
font-weight:normal
}
</style>
<![endif]-->
<!--[if lte IE 6]>
<style>
#ads {display:none;}
#adsie {clear:both; text-align:center; width:750px; margin-top:10px;}
</style>
<![endif]-->
</head>
<body>
<div id="wrapper"/>
<div id="head"/>
<div id="positioner"/>
<div class="menu">
<a class="outer" href="">XHTML/CSS
<table class="first"><tr><td>
<a class="inner" href="">标准</a>
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</td></tr></table>
</a>
<a class="outer" href="">XHTML/CSS
<table class="first"><tr><td>
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</td></tr></table>
</a>
<a class="outer" href="">LAYOUTS
</a>
</div></body></html>
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd" [ <!ELEMENT a (#PCDATA | table)* > ]>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" >
<head>
<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=UTF-8" />
<title>纯CSS下拉菜单,兼容IE和FF</title>
<style type="text/css">
body {color:#fff;}
#wrapper color:#000;}
.red {color:#c00;}
#info {margin-top:20px;}
#info h1 {font-size:3em; text-align:center; font-family: georgia, "times new roman", serif;}
#head {height:145px; border:0;}
#positioner {clear:both; position:relative; left:1px; z-index:100;}
#ads {position:relative; z-index:10;}
.menu {font-size:12px;position:relative;z-index:100;}
#noniemenu {position:absolute;}
#noniemenu .holder ul {padding:0; margin:0;}
#noniemenu .holder ul li {list-style-type: none;}
#noniemenu .holder li {}
#noniemenu .holder li ul {display: none;}
#noniemenu .holder li:hover > ul#a3 {display:block; position:absolute; left:105px; margin-top:-20px; border:1px solid #000;}
#noniemenu .holder .bold {font-weight:bold;}
#noniemenu .holder {
color:#fff;
width:104px;
height:18px;
display:block;
overflow:hidden;
float:left;
border:1px solid #000;
margin-right:1px;
font-size:10px;
}
#noniemenu .holder:hover {
height:auto;
}
#noniemenu a.outer, #noniemenu a.outer:visited {
color:#fff;
width:104px;
line-height:18px;
display:block;
background:#e09222;
text-align:center;
text-decoration:none;
font-family: verdana, arial, sans-serif;
}
#noniemenu a.outer:hover {
background:#697210;
overflow:visible;
}
#noniemenu div.open {display:none;}
#noniemenu a.inner, #noniemenu a.inner:visited {
display:block;
width:104px;
height:18px;
line-height:18px;
border-bottom:1px solid #000;
text-decoration:none;
color:#000;
background:#eee;
text-align:center;
}
#noniemenu a.second {font-weight:bold;}
#noniemenu a.inner:hover {
background:#add;
}
</style>
<!--[if lte IE 6]>
<style type="text/css">
body {margin-top:-8px;}
#head {height:147px;}
#noniemenu {display:none;}
.menu {display:block; position:absolute;}
.menu a.outer, .menu a.outer:visited {
color:#fff;
width:104px;
height:18px;
display:block;
background:#e09222;
border:1px solid #000;
margin-right:1px;
text-align:center;
float:left;
text-decoration:none;
font-family: verdana, arial, sans-serif;
font-size:10px;
line-height:18px;
overflow:hidden;
}
.menu a.outer:hover {
background:#697210;
overflow:visible;
}
.menu a.outer:hover table.first {
display:block;
background:#eee;
border-collapse:collapse;
}
.menu a.inner, .menu a.inner:visited {
display:block;
width:102px;
height:18px;
border-bottom:1px solid #000;
text-decoration:none;
color:#000;
font-family: verdana, arial, sans-serif;
font-size:10px;
text-align:center;
}
.menu a.inner:hover {
background:#add;
}
.menu a.outer table.first a.second {
height:18px;
line-height:18px;
overflow:hidden;
font-weight:bold;
}
.menu a.outer table.first a.second:hover {
position:relative;
overflow:visible;
}
.menu a.outer table.first a.second:hover table {
position:absolute;
top:-2px;
left:102px;
border-collapse:collapse;
background:#eee;
border:1px solid #000;
font-weight:normal
}
</style>
<![endif]-->
<!--[if lte IE 6]>
<style>
#ads {display:none;}
#adsie {clear:both; text-align:center; width:750px; margin-top:10px;}
</style>
<![endif]-->
</head>
<body>
<div id="wrapper"/>
<div id="head"/>
<div id="positioner"/>
<div class="menu">
<a class="outer" href="">XHTML/CSS
<table class="first"><tr><td>
<a class="inner" href="">标准</a>
<a class="inner" href="">技术文章</a>
<a class="inner" href="">常见问题</a>
<a class="inner" href="">布局教程专题</a>
<a class="inner second" href="" title="Hover/click with no active/focus borders">AJAX >
<table><tr><td>
<a class="inner" href="" title="Styling forms">AJAX教程</a>
</td></tr></table>
</a>
<a class="inner" href="">CSS菜单</a>
<a class="inner" href="">滚动条相关</a>
<a class="inner" href="">圆角矩形专题</a>
<a class="inner" href="">CSS特效欣赏专题</a>
</td></tr></table>
</a>
<a class="outer" href="">XHTML/CSS
<table class="first"><tr><td>
<a class="inner" href="">PHP</a>
<a class="inner" href="">ASP</a>
<a class="inner" href="">ASP.NET</a>
<a class="inner" href="">JSP</a>
<a class="inner" href="">SQL</a>
<a class="inner" href="">Flash</a>
<a class="inner" href="">Dreamweaver</a>
</td></tr></table>
</a>
<a class="outer" href="">LAYOUTS
</a>
</div></body></html>