<%@page pageEncoding="utf-8"
contentType="text/html;charset=utf-8"%>
<html>
<head>
<script type="text/javascript">
//step1 获得XmlHttpRequest对象。
function getXmlHttpRequest(){
var xmlHttpRequest = null;
if ((typeof XMLHttpRequest) != 'undefined') {
xmlHttpRequest = new XMLHttpRequest();
} else {
xmlHttpRequest = new ActiveXObject('Microsoft.XMLHttp');
}
return xmlHttpRequest;
}
function valiusername(){
//step1 获得XmlHttpRequest对象。
var xhr = getXmlHttpRequest();
var value = document.getElementById("username").value;
//step2 使用XmlHttpRequest对象向服务器发送请求。发送get请求
xhr.open("get","valiusername.do?username=" + encodeURI(value),true);
//step4 使用服务器返回的数据更新页面。
xhr.onreadystatechange = function(){
if(xhr.readyState == 4){
if(xhr.status == 200){
var txt = xhr.responseText;
var obj = document.getElementById('username_msg');
obj.innerHTML = txt;
}else{
var obj = document.getElementById('username_msg');
obj.innerHTML = 'system error';
}
}else{
var obj = document.getElementById('username_msg');
obj.innerHTML = 'checking...';
}
};
xhr.send(null);
}
function valiusername2(){
var xhr = getXmlHttpRequest();
var value = document.getElementById("username").value;
xhr.open("post","valiusername.do",true);
xhr.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
xhr.onreadystatechange = function(){
if(xhr.readyState == 4){
if(xhr.status == 200){
var txt = xhr.responseText;
var obj = document.getElementById('username_msg');
obj.innerHTML = txt;
}else{
var obj = document.getElementById('username_msg');
obj.innerHTML = 'system error';
}
}else{
var obj = document.getElementById('username_msg');
obj.innerHTML = 'checking...';
}
};
xhr.send("username=" + value);
}
</script>
</head>
<body style="font-size:30px;">
<form action="regist.do" method="post">
用户名:<input id="username" name="username"
onblur="valiusername();"/>
<span style="color:red;" id="username_msg"></span>
<br/>
密码:<input name="pwd"/>
<br/>
<input type="submit" value="确认"/>
</form>
</body>
</html>
package web;
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 UserServlet extends HttpServlet {
public void service(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException {
request.setCharacterEncoding("utf-8");
String uri =request.getRequestURI();
String path = uri.substring(uri.lastIndexOf("/"),uri.lastIndexOf("."));
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
if(path.equals("/valiusername")){
System.out.println("valiusername...");
String username = request.getParameter("username");
System.out.println("username:" + username);
if(username.equals("张三")){
out.println("用户名已经存在.");
}else{
out.println("可以使用");
}
}else if(path.equals("/regist")){
}
}
}
