xmlhttprequest 原生使用

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package com.ajax.web;import java.io.IOException;import java.io.PrintWriter;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.ajax.dao.Dao;public class ShwServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html;charset=gbk");PrintWriter out = response.getWriter();String uname = request.getParameter("uname");String name = new String(uname.getBytes("iso-8859-1"), "gbk");// Dao dao = new Dao();// List<String> list = dao.find(name);StringBuffer sf = new StringBuffer();for (String s : list) {sf.append("<div onmouseover='over(this)' " +"onclick='myclick(this)'  " +"onmouseout='out(this)'>"+s+"</div>");}out.print(sf.toString());out.close();}}

////这是我的ajax脚本文件var req =null; //声明ajax的核心对象，从是没有初始化//响应jsp页面中的函数function show(){//取到页面中的文本框控件var name = document.getElementById("name");//取到控件中的值var val = name.value;if(val==""){mydiv.innerHTML="";return;}else{//封装一个请求servlet路径的url地址，同时把参数以url重写的方式传递var url = "abc?uname="+val;sendRequest(url);}}//编写方法，根据不同的浏览器创建核心对象 XMLHttpRequest，function  createReq(){//非IEif(window.XMLHttpRequest){req = new XMLHttpRequest();}else if(window.ActiveXObject){try{req = new ActiveXObject("Msxml2.XMLHTTP");}catch(e){req = new ActiveXObject("Microsoft.XMLHTTP");}}}//利用核心对象和后台交互function sendRequest(url){//准备交互//1、调用方法初始化核心对象createReq();//2、准备建立异步请求//req.open(选择servlet的处理方式,地址,同步还是异步);req.open("GET",url,true);//3、编写委托，委托一个方法来处理请求的返回结果//req.onreadystatechange =被委托的函数名称req.onreadystatechange = process;//4、真正的发送请求到后台req.send(null);}//当返回值来了以后，由被委托的函数来处理function process(){//首先判断异步是否成功与后台交互//req.readystate==4  表示，前台与后台，成功交互了一次if(req.readystate==4){//交互成功以后，还要判断请求是否成功处理if(req.status==200){//定制一个变量，获得后台的返回值var res = req.responseText;//req.responseText 它可以获得servlet中，流所输出的内容mydiv.innerHTML = res;}}}//处理悬停事件function over(obj){obj.style.backgroundColor="lime";}function out(obj){obj.style.backgroundColor="white";}function myclick(obj){var val = obj.innerHTML;document.getElementById("name").value=val;mydiv.innerHTML="";}

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%><html>  <head>  <script type="text/javascript" src="js/script.js"></script>  </head>    <body>  <table>  <Tr>  <Td>  <input type="text" name="name" onkeyup="show()"/>  </Td>  </Tr>  <Tr>  <Td>  <div id="mydiv" style="border-style: groove"></div>  </Td>  </Tr>  </table>  </body></html>

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