原文：http://www.blogjava.net/eamoi/archive/2005/11/01/17639.html
有网友反映说《AJAX开发简略》配文代码不全。其实应该是全的，只是要把包括框架和两个示例的程序都整合起来看。这里把全部的代码贴出来，需要的朋友可以看看。
sample1_1.jsp：
<%@ page contentType="text/html; charset=gb2312" language="java" errorPage="" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
<script language="javascript">
var http_request = false;
function send_request(url) {//初始化、指定处理函数、发送请求的函数
http_request = false;
//开始初始化XMLHttpRequest对象
if(window.XMLHttpRequest) { //Mozilla 浏览器
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {//设置MiME类别
http_request.overrideMimeType('text/xml');
}
}
else if (window.ActiveXObject) { // IE浏览器
try {
http_request = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
http_request = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
if (!http_request) { // 异常，创建对象实例失败
window.alert("不能创建XMLHttpRequest对象实例.");
return false;
}
http_request.onreadystatechange = processRequest;
// 确定发送请求的方式和URL以及是否同步执行下段代码
http_request.open("GET", url, true);
http_request.send(null);
}
// 处理返回信息的函数
function processRequest() {
if (http_request.readyState == 4) { // 判断对象状态
if (http_request.status == 200) { // 信息已经成功返回，开始处理信息
alert(http_request.responseText);
} else { //页面不正常
alert("您所请求的页面有异常。");
}
}
}
function userCheck() {
var f = document.form1;
var username = f.username.value;
if(username=="") {
window.alert("用户名不能为空。");
f.username.focus();
return false;
}
else {
send_request('sample1_2.jsp?username='+username);
}
}
</script>
<link href="css/style.css" rel="stylesheet" type="text/css">
</head>
<body>
<form name="form1" action="" method="post">
用户名：<input type="text" name="username" value="">
<input type="button" name="check" value="唯一性检查" onClick="userCheck()">
<input type="submit" name="submit" value="提交">
</form>
<!--span
style="cursor: pointer; text-decoration: underline"
onclick="send_request('2.jsp?username=educhina')">Send a
request</span-->
</body>
</html>
sample1_2.jsp：
<%@ page contentType="text/html; charset=gb2312" language="java" errorPage="" %>
<%
String playPos = request.getParameter("playPos");
if("pos_1".equals(playPos)) out.print("用户名已经被注册，请更换一个用户名。");
else out.print("用户名尚未被使用，您可以继续。");
%>
sample2_1.jsp：
<%@ page contentType="text/html; charset=gb2312" language="java" errorPage="" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
<script language="javascript">
var http_request = false;
var currentPos = null;
function send_request(url) {//初始化、指定处理函数、发送请求的函数
http_request = false;
//开始初始化XMLHttpRequest对象
if(window.XMLHttpRequest) { //Mozilla 浏览器
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {//设置MiME类别
http_request.overrideMimeType('text/xml');
}
}
else if (window.ActiveXObject) { // IE浏览器
try {
http_request = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
http_request = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
if (!http_request) { // 异常，创建对象实例失败
window.alert("不能创建XMLHttpRequest对象实例.");
return false;
}
http_request.onreadystatechange = processRequest;
// 确定发送请求的方式和URL以及是否同步执行下段代码
http_request.open("GET", url, true);
http_request.send(null);
}
// 处理返回信息的函数
function processRequest() {
if (http_request.readyState == 4) { // 判断对象状态
if (http_request.status == 200) { // 信息已经成功返回，开始处理信息
//alert(http_request.responseText);
document.getElementById(currentPos).innerHTML = http_request.responseText;
} else { //页面不正常
alert("您所请求的页面有异常。");
}
}
}
//显示部门下的岗位
function showRoles(obj) {
document.getElementById(obj).parentNode.style.display = "";
document.getElementById(obj).innerHTML = "正在读取数据..."
currentPos = obj;
send_request("sample2_2.jsp?playPos="+obj);
}
</script>
<link href="css/style.css" rel="stylesheet" type="text/css">
</head>
<body>
<table width="200" border="0" cellspacing="0" cellpadding="0">
<tr>
<td height="20"><a href="javascript:void(0)"
onClick="showRoles('pos_1')">经理室</a></td>
</tr>
<tr style="display:none">
<td height="20" id="pos_1"> </td>
</tr>
<tr>
<td height="20"><a href="javascript:void(0)"
onClick="showRoles('pos_2')">开发部</a></td>
</tr>
<tr style="display:none ">
<td id="pos_2" height="20"> </td>
</tr>
</table>
<!--a href="javascript:void(0)" onClick="showRoles('pos_1')">测试</a-->
<!--span
style="cursor: pointer; text-decoration: underline"
onclick="send_request('2.jsp?username=educhina')">Send a
request</span-->
</body>
</html>
sample2_2.jsp：
<%@ page contentType="text/html; charset=gb2312" language="java" errorPage="" %>
<%
String playPos = request.getParameter("playPos");
if("pos_1".equals(playPos)) out.print(" 总经理<br> 副总经理");
else if("pos_2".equals(playPos)) out.println(" 总工程师<br> 软件工程师");
%>