代码如下：
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<meta name="Keywords" content="" />
<meta name="description" content="" />
<style type="text/css">
/*
这以下是重置样式
Remove margin padding */
body,h1,h2,h3,h4,h5,h6,hr,p,blockquote,dl,dt,dd,ul,ol,li,pre,form,fieldset,legend,button,input,textarea,th,td { margin:0; padding:0; }
/* Default Font */
body,button,input,select,textarea { font:12px/1.5 \5b8b\4f53,arial,sans-serif; }
h1,h2,h3,h4,h5,h6 { font-size:100%; }
address,cite,dfn,em,var { font-style:normal; }
code,kbd,pre,samp { font-family:courier new,courier,monospace; }
small { font-size:12px; }
ul,ol { list-style:none; }
a { text-decoration:none; }
a:hover { text-decoration:underline; }
sup { vertical-align:text-top; }
sub { vertical-align:text-bottom; }
legend { color:#000; }
fieldset,img { border:0; }
button,input,select,textarea{ font-size:100%; }
table { border-collapse:collapse; border-spacing:0; }
/* Remove Float */
.clear { display:block; height:0; overflow:hidden; clear:both; }
.clearfix:after { content:‘\20‘; display:block; height:0; clear:both; }
.clearfix { *zoom:1; }
/* 重置样式结束 */
</style>
</head>
<body style="padding-top:50px;">
<style type="text/css">
.nav { height:25px; font-family:"Microsoft Yahei"; }
.nav ul li { position:relative; float:left; display:inline; margin-left:1px; width:100px; text-align:center; height:25px; line-height:25px; }
.nav ul li a { transition:background 500ms linear; text-decoration:none; display:block; text-shadow:0px 1px 0px #000; width:100%; height:100%; text-align:center; background-color:#089478; color:#FFF; }
.nav ul li a:hover, .nav ul li a.current { background-color:#076451; text-decoration:none; }
.nav .sub-nav { display:none; position:absolute; top:24px; left:0px; padding-top:10px; }
.nav .sub-nav li { float:none; display:block; width:100px; height:30px; line-height:30px; }
.nav .sub-nav .triangle { position:absolute; left:50%; top:5px; margin-left:-3px; display:block; width:0; height:0; overflow:hidden; line-height:0; font-size:0; border-bottom:5px solid #089478; border-top:none; border-left:5px solid #FFF; border-right:5px solid #FFF; }
</style>
<div class="nav">
<ul class="clearfix">
<li>
<a href="#">导航1</a>
<ul class="sub-nav">
<span class="triangle"></span>
<li><a href="#">子导航1</a></li>
<li><a href="#">子导航2</a></li>
<li><a href="#">子导航3</a></li>
<li><a href="#">子导航4</a></li>
<li><a href="#">子导航5</a></li>
</ul>
</li>
<li>
<a href="#">导航2</a>
<ul class="sub-nav">
<span class="triangle"></span>
<li><a href="#">子导航1</a></li>
<li><a href="#">子导航2</a></li>
<li><a href="#">子导航3</a></li>
<li><a href="#">子导航4</a></li>
<li><a href="#">子导航5</a></li>
</ul>
</li>
<li>
<a href="#">导航3</a>
<ul class="sub-nav">
<span class="triangle"></span>
<li><a href="#">子导航1</a></li>
<li><a href="#">子导航2</a></li>
<li><a href="#">子导航3</a></li>
<li><a href="#">子导航4</a></li>
<li><a href="#">子导航5</a></li>
</ul>
</li>
<li>
<a href="#">导航4</a>
<ul class="sub-nav">
<span class="triangle"></span>
<li><a href="#">子导航1</a></li>
<li><a href="#">子导航2</a></li>
<li><a href="#">子导航3</a></li>
<li><a href="#">子导航4</a></li>
<li><a href="#">子导航5</a></li>
</ul>
</li>
<li>
<a href="#">导航5</a>
<ul class="sub-nav">
<span class="triangle"></span>
<li><a href="#">子导航1</a></li>
<li><a href="#">子导航2</a></li>
<li><a href="#">子导航3</a></li>
<li><a href="#">子导航4</a></li>
<li><a href="#">子导航5</a></li>
</ul>
</li>
</ul>
</div>
<script type="text/javascript" src="http://cdn.bootcss.com/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
$(‘.nav ul li‘).hover(function(){
$(this).children(‘a‘).addClass(‘current‘);
$(this).children(‘ul‘).stop(true,true).fadeIn(400);
}, function(){
$(this).children(‘ul‘).stop(true,true).fadeOut(400);
$(this).children(‘a‘).removeClass(‘current‘);
});
</script>
</body>
</html>