浏览器窗口滚动加载数据采用异步形式从后台加载数据

%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ScrollLoadData.aspx.cs" Inherits="WebApplication1.ScrollLoadData" %>

!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>滚动加载数据库数据/title>
script src="../Scripts/jquery-1.4.1-vsdoc.js" type="text/javascript">/script>
script src="../Scripts/jquery-1.4.1.js" type="text/javascript">/script>
script src="../Scripts/jquery-1.4.1.min.js" type="text/javascript">/script>
script type="text/javascript">
$(document).ready(function () {

var range = 50; //距下边界长度/单位px
var elemt = 500; //插入元素高度/单位px
var maxnum = 20; //设置加载最多次数
var num = 1;
var totalheight = 0;
var main = $("#content"); //主体元素
$(window).scroll(function(){
var srollPos = $(window).scrollTop(); //滚动条距顶部距离(页面超出窗口的高度)

totalheight = parseFloat($(window).height()) + parseFloat(srollPos);
if (($(document).height() - range) = totalheight num != maxnum) {
$.ajax({
url: "../demo/HandlerDemo.ashx",//显示数据的方法页
type: "GET",
data: "name=json",
dataType: "json",
//cache: false,
success: function (data) {
data = eval(data);
var varHtml = "";
varHtml = "ul>"
$(data).each(function (i) {
varHtml += "li>" + data[i].ID + ":" + data[i].Event + "/li>"; //ID 和Event为数据库映射的字段
});
varHtml += "/ul>";
main.append("div style='border:0px solid tomato;margin-top:20px;color:#ac" + (num % 20) + (num % 20) + ";height:" + elemt + "' >hello world" + srollPos + "br />"+varHtml + "---" + num + "/div>");
},
error: function () {
alert("error");
}

});

num++;
}
});
});
/script>
style type="text/css">
li
{
list-style-type:none;
float:left;
padding-left:20px;

}
/style>
/head>
body>
form id="form1" runat="server">
div id="content" style="height:960px">
div id="follow">this is a scroll test;br/> 页面下拉自动加载内容/div>
div style='border:1px solid tomato;margin-top:20px;color:#ac1;height:800' >hello world test DIV/div>
/div>

/form>
/body>
/html>