<!DOCTYPE html>
<html>
<head>
<meta charset=
"UTF-8"
>
<title>js滚动到指定位置导航栏固定顶部</title>
<style type=
"text/css"
>
body{height: 2500px; margin: 0; padding: 0;}
.banner{height: 250px; width: 100%; background: #e5e5e5;}
.bignav{width: 100%; background: #000;}
.nav{ background:#000; width: 1200px; margin: 0 auto; height: 45px;}
.nav a{display: block; width: 200px;float: left; color: #fff; text-decoration: none; text-align: center; line-height: 45px;}
</style>
</head>
<body>
<div
class
=
"banner"
>
</div>
<div
class
=
"bignav"
id=
"bignav"
>
<div
class
=
"nav"
>
<a href=
"#"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
>首页</a>
<a href=
"#"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
>首页</a>
<a href=
"#"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
>首页</a>
<a href=
"#"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
>首页</a>
<a href=
"#"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
>首页</a>
<a href=
"#"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
rel=
"external nofollow"
>首页</a>
</div>
</div>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
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<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<p>其他内容</p>
<script type=
"text/javascript"
>
window.onscroll=
function
(){
var
topScroll =document.body.scrollTop;
var
bignav = document.getElementById(
"bignav"
);
if
(topScroll > 250){
bignav.style.position = 'fixed';
bignav.style.top = '0';
bignav.style.zIndex = '9999';
}
else
{
bignav.style.position = '
static
';
}
}
</script>
</body>
</html>