首先在ASP.Net創建兩個WebForm頁，分別命名爲Default1，Default2。下面給出代碼清單：
//Default1.aspx
<%@ Page Language="C#" Debug="true" AutoEventWireup="true" CodeFile="Default1.aspx.cs" Inherits="Default1" %>
<!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>無標題頁</title>
<script type="text/Javascript">
var XmlHttp;
function createXmlHttpRequest()
{
if (window.XmlHttpRequest)
{
XmlHttp = new XmlHttpRequest();
}
else if (window.ActiveXObject)
{
try
{
XmlHttp = new ActiveXObject("MsXml2.XmlHTTP");
}
catch (e1)
{
try
{
XmlHttp = new ActiveXObject("Microsoft.XmlHTTP");
}
catch (e2)
{}
}
}
return XmlHttp;
}
function doStart() {
createXmlHttpRequest();
var url = "Default2.aspx?task=reset";
XmlHttp.open("POST", url, true);
XmlHttp.onreadystatechange = startCallback;
XmlHttp.send(null);
}
function startCallback() {
if (XmlHttp.readyState == 4) {
if (XmlHttp.status == 200) {
setTimeout("pollServer()", 1000);
refreshTime();
}
else {
alert("HTTP error: "+XmlHttp.status);
}
}
}
function pollServer() {
createXmlHttpRequest();
var url = "Default2.aspx?task=foo";
XmlHttp.open("POST", url, true);
XmlHttp.onreadystatechange = pollCallback;
XmlHttp.send(null);
}
function refreshTime(){
var time_span = document.getElementById("time");
var time_val = time_span.innerHTML;
var int_val = parseInt(time_val);
var new_int_val = int_val - 1;
if (new_int_val > -1) {
setTimeout("refreshTime()", 1000);
time_span.innerHTML = new_int_val;
} else {
time_span.innerHTML = 1;
}
}
function pollCallback() {
if (XmlHttp.readyState == 4) {
if (XmlHttp.status == 200) {
var message = XmlHttp.responseXml.getElementsByTagName("message")[0].firstChild.data;
if (message != "done") {
var new_row = createRow(message);
var table = document.getElementById("dynamicUpdateArea");
var table_body = table.getElementsByTagName("tbody").item(0);
var first_row = table_body.getElementsByTagName("tr").item(1);
table_body.insertBefore(new_row, first_row);
setTimeout("pollServer()", 1000);
refreshTime();
}
}
else {
alert("HTTP error: "+XmlHttp.status);
}
}
}
function createRow(message) {
var row = document.createElement("tr");
var cell = document.createElement("td");
var cell_data = document.createTextNode(message);
cell.appendChild(cell_data);
row.appendChild(cell);
return row;
}
</script>
</head>
<body>
<form id="form1" runat="server" >
<h1>AJAX Dynamic Update Example</h1>
This page will automatically update itself:
<input type="button" value="Launch" id="go" οnclick="doStart();"/>
<p/>
Page will refresh in <span id="time">1</span> seconds.
<p/>
<table id="dynamicUpdateArea" align="left">
<tbody>
<tr id="row0"><td></td></tr>
</tbody>
</table>
</form>
</body>
</html>