本文实例讲述了jQuery实现的监听导航滚动置顶状态功能。分享给大家供大家参考，具体如下：
1. js代码
/**
* Created by EDUASK on 2016/5/20.
*/
$(function(){
//引入id标签;
var navtive=$("#native");
//设置导航标签为置顶;
var offsetTop=navtive.offset().top;
//定义一个监听高度;
var scrollHeight=$(document).scrollTop;
fn(navtive,offsetTop);
//设置监听事件;
$(window).scroll(function(){
fn(navtive,offsetTop);
});
//调用方法;
function fn(navtive,offsetTop){
var scrollHeight=$(document).scrollTop();
if(offsetTop>scrollHeight){
navtive.css("top",offsetTop);
}else{
navtive.css("top",scrollHeight);
}
}
});
2. html代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>监听导航滚动置顶</title>
<!--css样式;-->
<style type="text/css">
/*添加导航条的样式;
*/
#native{
background: blue;
width: 100%;
height: 20px;
color: red;
position: absolute;
top: 100px;
left: 0;
text-align: center;
}
</style>
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
<script type="text/javascript" src="监听导航滚动置顶.js">
</script>
</head>
<body>
<p id="top">ddddd</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<div id="native">欢迎访问我的导航条</div>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<a href="#top" rel="external nofollow" >回到顶部</a>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
<p>aaaaaaaaaaaa</p>
</body>
</html>
感兴趣的朋友可以使用在线HTML/CSS/JavaScript代码运行工具：http://tools.softyun.net/code/HtmlJsRun测试运行效果。
希望本文所述对大家jQuery程序设计有所帮助。
