<!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>顶端浮动导航效果</title>
<style type="text/css">
body,h1,ul{margin:0;}
ul li{list-style-type:none;}
#header{width:100%;border-top:solid 1px #ccc;border-bottom:solid 1px #ccc;text-align:center;}
h1{padding:10px 0;color:#D74452;}
.nav{width:1000px;background:#fff;margin:20px auto 0;border:solid 1px #ccc;zoom:1;border-radius:5px;box-shadow:0 1px 6px rgba(0,0,0,0.1);color:#D74452;}
.nav_scroll{position:fixed;width:100%;margin:0;left:0;top:0;}
.nav:after{content:"";display:block;height:0;clear:both;visibility:hidden;}
.nav ul li{float:left;margin:0 20px;height:30px;line-height:30px;}
.nav ul li a{cursor:pointer; }
.nav ul li a:hover{text-decoration:underline;}
h2{height:400px;line-height:400px;}
</style>
<script src="js/jquery.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(document).ready(function(){
var topMain=$("#header").height()+20//是头部的高度加头部与nav导航之间的距离。
var nav=$(".nav");
$(window).scroll(function(){
if ($(window).scrollTop()>topMain){//如果滚动条顶部的距离大于topMain则就nav导航就添加类.nav_scroll，否则就移除。
nav.addClass("nav_scroll");
}
else
{
nav.removeClass("nav_scroll");
}
});
})
</script>
</head>
<body>
<div id="header"><h1>花瓣</h1></div><!--header-->
<div class="nav">
<ul>
<li><a>关注</a></li>
<li><a>最新</a></li>
<li><a>最热</a></li>
<li><a>视频</a></li>
<li><a>家居</a></li>
<li><a>旅行</a></li>
</ul>
</div><!--nav-->
<div style="background:#f9f9f9;color:#000;" id="cont">
<h2>1</h2>
<h2>2</h2>
<h2>3</h2>
<h2>4</h2>
<h2>5</h2>
<h2>6</h2>
<h2>7</h2>
<h2>8</h2>
<h2>1</h2>
<h2>2</h2>
<h2>3</h2>
<h2>4</h2>
<h2>5</h2>
<h2>6</h2>
<h2>7</h2>
<h2>8</h2>
<h2>1</h2>
<h2>2</h2>
<h2>3</h2>
<h2>4</h2>
<h2>5</h2>
<h2>6</h2>
<h2>7</h2>
<h2>8</h2>
<h2>1</h2>
<h2>2</h2>
<h2>3</h2>
<h2>4</h2>
<h2>5</h2>
<h2>6</h2>
<h2>7</h2>
<h2>8</h2>
<h2>1</h2>
<h2>2</h2>
<h2>3</h2>
<h2>4</h2>
<h2>5</h2>
<h2>6</h2>
<h2>7</h2>
<h2>8</h2>
</div>
</body>
</html>
