Ajax概述(必威体育精装版).ppt

Best Wishes! This report was produced by Broadengate Systems Training Centre Thanks! * checkuser.jsp源代码: %@ page language=java import=java.util.* pageEncoding=gbk% % String path = request.getContextPath(); String basePath = request.getScheme()+://+request.getServerName()+:+request.getServerPort()+path+/; % !DOCTYPE HTML PUBLIC -//W3C//DTD HTML 4.01 Transitional//EN html head base href=%=basePath% titleMy JSP checkuser.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=keywords content=keyword1,keyword2,keyword3 meta http-equiv=description content=This is my page !-- link rel=stylesheet type=text/css href=styles.css -- script type=text/javascript var httpRequest; //创建XMLHttpRequest对象 function createXMLHttpRequest(){ if(window.ActiveXObject){ //说明是IE浏览器 httpRequest = new ActiveXObject(Microsoft.XMLHTTP); }else{ //其他浏览器 httpRequest = new XMLHttpRequest(); } } //发送请求 function sendRequest(url){ alert(url); httpRequest.onreadystatechange = handleResult; //设置返回结果的处理函数 httpRequest.open(get, url, true); httpRequest.setRequestHeader(Cache-Control, no-cache); httpRequest.send(null); } //处理返回结果 function handleResult(){ if(httpRequest.readyState == 4){ if(httpRequest.status == 200){ alert(httpRequest.responseText); }else{ alert(指定页面不存在); } } } /script /head body 用户名:input name=usernamebr input type=button value=检查用户名是否被使用 onclick=createXMLHttpRequest();sendRequest(CheckUserServlet?un= + document.all.username.value); /body /html CheckUserServlet.java源代码: package com.aptech.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class CheckUserServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse