<%@ page language="java" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>校验用户名是否存在</title>
<script charset="gb2312" type="text/javascript" src="./register.js"> </script>
</head>
<body>
<center>
<form action="" enctype="application/x-www-form-urlencoded">
<h3>请填写用户注册信息</h3>
<table border="1">
<tr>
<td>用户名:</td>
<td><input type="text" name="username" value="" id="username">
<div id="divcheck"></div>
<input type="button" name="checkusername" value="查看用户名" id="checkusername"></td>
</tr>
<tr>
<td>密码:</td>
<td><input type="password" name="psw" value=""></td>
</tr>
<tr>
<td>确认密码:</td>
<td><input type="password" name="confpsw" value=""></td>
</tr>
<tr>
<td>出生日期:</td>
<td><input type="text" name="birthday" value=""></td>
</tr>
</table>
</form>
</center>
</body>
</html>
window.onload=function(){
//<input type="button" name="checkusername" value="查看用户名" id="checkusername"></td>
document.getElementById("checkusername").onclick=function(){
//1.
var xmlRequest= ajaxFunction();
//<input type="text" name="username" value="" id="username">
var username = document.getElementById("username").value;
//2.
xmlRequest.onreadystatechange=function(){
if(xmlRequest.readyState==4){
if(xmlRequest.status==200||xmlRequest.status==304){
var info = xmlRequest.responseText;
//获取层 <div id="divcheck"></div>
document.getElementById("divcheck").innerHTML=info;
}
}
}
//3.
xmlRequest.open("post","../registerServlet?timeStamp="+new Date().getTime(),true);
xmlRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
//4.
xmlRequest.send("username="+username);
}
}
/**
* 该函数创建XmlHttpRequest对象
*/
function ajaxFunction(){
var xmlHttp;
try{ // Firefox, Opera 8.0+, Safari
xmlHttp=new XMLHttpRequest();
}
catch (e){
try{// Internet Explorer
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e){
try{
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e){}
}
}
return xmlHttp;
}
package cn.ajax;
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 RegisterServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html");
PrintWriter out = response.getWriter();
System.out.println("register dopost");
String username = request.getParameter("username");
if ("sa".equals(username)) {
out.println("用户名已经存在");
}else {
out.println("用户名可以使用");
}
}
}