<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="菜单栏在页面顶部.WebForm1" %> <!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 runat="server"> <title></title> <script src="Scripts/jquery-1.4.1.min.js" type="text/javascript"></script> <script type="text/javascript"> $(document).ready(function(){ //获取要定位元素距离浏览器顶部的距离 var navH = $(".hb").offset().top; //滚动条事件 $(window).scroll(function () { //获取滚动条的滑动距离 var scroH = $(this).scrollTop(); //滚动条的滑动距离大于等于定位元素距离浏览器顶部的距离，就固定，反之就不固定 if (scroH >= navH) { $(".hb").css({ "position": "fixed", "top": 0 }); } else if (scroH < navH) { $(".hb").css({ "position": "static" }); } }) }) </script> </head> <body> <form id="form1" runat="server"> <div class="hb" style="height:100px;100%;background:#9966FF">移动到顶部固定不变</div> <div style="background:#003366;height:500px;">空div</div> <div style="background:#ff0000;height:1500px;">空div</div> <div style="background:#ccc;height:1500px;">空div</div> </form> </body> </html>