软件测试中的一个ajax的经典测试用例

[1]写index.jsp文件
　<%@ page contentType="text/html;charset=gb2312"%>
　<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
　<html>
　<head>

<title>My JSP 'index.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
　<meta http-equiv="cache-control" content="no-cache">
　<meta http-equiv="expires" content="0">
　<meta http-equiv="description" content="This is my page">
　<link rel="stylesheet" type="text/css" href="styles.css">
　</head>

<body>
　<script type="text/javascript">
　var req;

function validate() {
　var idField = document.getElementById("userid");
　var url = "servlet/ValidateServlet?id=" + escape(idField.value);
　if (window.XMLHttpRequest) {
　alert("0");
　req = new XMLHttpRequest();
　}else if (window.ActiveXObject) {
　alert("1");
　req = new ActiveXObject("Microsoft.XMLHTTP");
　}
　if(req){
　req.open("GET"， url， true);
　req.onreadystatechange = callback;
　req.send(null);
　}
　}
　function callback() {
　if (req.readyState == 4) {
　if (req.status == 200) {
　parseMessage();
　// update the HTML DOM based on whether or not message is valid
　}else{
　alert ("Not able to retrieve description" + req.statusText);
　}
　}
　}
　function parseMessage() {
　var message = req.responseXML.getElementsByTagName("message")[0];
　var name = req.responseXML.getElementsByTagName("name")[0];
　setMessage(message.firstChild.data，name.firstChild.data);
　}
　function setMessage(message，name) {
　var userMessageElement = document.getElementById("userIdMessage");
　userMessageElement.innerHTML = "<font color="red">" + message + " you "+name+"</font>";
　}
　</script>
　<div id="userIdMessage"></div>
　<input type="text"
　size="20"
　id="userid"
　name="id"
　onkeyup="validate();">
　</body>
　</html>
　
　[2] 写servlet/ValidateServlet.java类
　/*
　* 创建日期 2005-8-3
　*
　* TODO 要更改此生成的文件的模板，请转至
　* 窗口 － 项 － Java － 代码样式 － 代码模板
　*/
　package com;//com包需要自己创建.

import java.io.IOException;
　import java.io.PrintWriter;
　import java.util.HashMap;

import javax.servlet.ServletConfig;
　import javax.servlet.ServletContext;
　import javax.servlet.ServletException;
　import javax.servlet.http.HttpServlet;
　import javax.servlet.http.HttpServletRequest;
　import javax.servlet.http.HttpServletResponse;

/**
　* @author Administrator
　*
　* TODO 要更改此生成的类型注释的模板，请转至
　* 窗口 － 项 － Java － 代码样式 － 代码模板
　*/
　public class ValidateServlet extends HttpServlet {

/**
　* Constructor of the object.
　*/

private ServletContext context;
　private HashMap users = new HashMap();

public ValidateServlet() {
　super();
　}