<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
<title>The JQ element is less than 0 suspended from the top window and greater than 0 to restore the original state</title>
<link rel="stylesheet" href="css/base.css" />
<script type="text/javascript" src="js/jquery-1.10.1.min.js"></script>
</head>
<body>
<div style="height: 200px; background: #06f;"></div>
<div style="height: 20px; background: #f60; z-index: 999; width: 100%;" class="headcall"></div>
<div style="height: 3000px; background: #ccc;"></div>
<script type="text/javascript">
$(function(){
headcall();
});
function headcall(){
var dh = $(".headcall");
var dhtop = dh.offset (). top;
//scroll monitor
$(window).scroll(function(){
if ($(window).scrollTop() >= dhtop){
dh.css({'position':'fixed','top':'0','left':'0'});}
else{
dh.css({'position':'static','top':'0','left':'0'});
}
});
}
</script>
</body>
</html>
Effect picture: