一、
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
#header{
background-color: red;
text-align: center;
height: 80px ;
line-height: 80px;
margin-bottom: 20px;
}
#nav{
background-color: blue;
height: 50px;
}
#aside{
float: left;
width: 100px;
height: 400px;
background-color: green;
}
.clearfix:after{
content: "";
clear: both;
display: block;
}
#content{
background-color: #ccc;
height: 800px;
padding: 10px;
}
#main{
height: 800px;
margin-left: 100px;
background-color: yellow;
}
#footer{
background-color: #666;
}
</style>
<script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/1.9.1/jquery.min.js"></script>
</head>
<body>
<div id="header">header</div>
<div id="nav">nav</div>
<div id="content" class="clearfix">
<div id="aside">aside</div>
<div id="main">main</div>
</div>
<div id="footer">
footer
</div>
<script>
var $cur=$("#nav"),
eleOffsetH=$cur.offset().top ,
eleOffsetW=$cur.offset().left,
eleHeight=$cur.height(),
eleWidth=$cur.width();
eleClone=$cur.clone();
$cur.before(eleClone);
eleClone.hide();
//思路 当nav滑动到顶部时，克隆体显示，本体fixed
$(window).on("scroll",function () {
var scrollH=$(window).scrollTop();
if (scrollH >= eleOffsetH) {
eleClone.show();
$cur.css({
"position":"fixed",
"left":eleOffsetW,
"top":0,
"width":eleWidth,
"height":eleHeight,
"z-index":999
}) ;
}
else {
eleClone.hide();
$cur.removeAttr("style")
}
})
</script>
</body>
</html>
</body>
</html>
二、
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
#ct{
width: 800px;
margin: 0 auto;
}
#header{
background-color: red;
text-align: center;
height: 80px ;
line-height: 80px;
margin-bottom: 20px;
}
.nav{
background-color: blue;
height: 50px;
}
.aside{
float: left;
width: 200px;
height: 400px;
background-color: green;
}
.clearfix:after{
content: "";
clear: both;
display: block;
}
.content{
height: 400px;
margin-bottom:20px ;
}
.main{
height: 400px;
margin-left: 210px;
background-color: yellow;
}
#footer{
background-color: #666;
}
</style>
<script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/1.9.1/jquery.min.js"></script>
</head>
<body>
<div id="ct">
<div id="header">header1</div>
<div class="part">
<div class="nav">nav1</div>
<div class="content clearfix">
<div class="aside">aside1</div>
<div class="main">main1</div>
</div>
</div>
<div class="part">
<div class="nav">nav2</div>
<div class="content,clearfix">
<div class="aside">aside2</div>
<div class="main">main2</div>
</div>
</div>
<div class="part">
<div class="nav">nav3</div>
<div class="content clearfix">
<div class="aside">aside3</div>
<div class="main">main3</div>
</div>
</div>
<div class="part">
<div class="nav">nav4</div>
<div class="content,clearfix">
<div class="aside">aside4</div>
<div class="main">main4</div>
</div>
</div>
<div id="footer">
footer
</div>
</div>
<script>
$(".nav").each(function () {
var $cur=$(this),
eleOffsetH=$cur.offset().top ,
eleOffsetW=$cur.offset().left,
eleHeight=$cur.height(),
eleWidth=$cur.width();
eleClone=$cur.clone();
$cur.before(eleClone);
eleClone.hide();
$(window).on("scroll",function () {
var scrollH=$(this).scrollTop();
if (scrollH >= eleOffsetH) {
if ($cur.data("isFixed")){return}
$cur.css({
"position":"fixed",
"left":eleOffsetW,
"top":0,
"width":eleWidth,
"height":eleHeight,
"z-index":999
});
$cur.data("isFixed",true);
eleClone.show();
}
else {
eleClone.hide();
$cur.removeAttr('style');
$cur.data("isFixed",false);
}
})
})
</script>
</body>
</html>
**本文版权归本人即简书笔名：该账户已被查封 所有，如需转载请注明出处。谢谢！ *
