ajax实现用户名存在,jqury和ajax实现用户名是否存在

--------------------------------------jsp代码-----------------------------------------------------

pageEncoding="utf-8"%>

String path = request.getContextPath();

String basePath =

request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>

/p>

Transitional//EN">

href="">

My JSP 'index.jsp' starting

page

content="no-cache">

content="no-cache">

content="0"> 

content="keyword1,keyword2,keyword3">

content="This is my page">

$(document).ready(function(){

// alert("加载成功");

//注册失去焦点事件

$("#loginName").blur(function

(){

alert("失去焦点");

//encodeURI(encodeURI($("#loginName").val())防止汉子乱码

var

url = "servlet/CheckLoginName2?name=" +

encodeURI(encodeURI($("#loginName").val()));

var mes; //要显示的信息

var cor; //文本设置的颜色

$.get(url,null,function(response){

//alert(url);

if(response == "true"){

alert(response);

//$("#divId").html(response);

cor

= "#ff0011";

//alert(response.childNodes[0].childNodes[0].nodeValue);

mes="用户名已经存在";

}else if(response="false"){

cor = "#00ff11";

mes="用户名可以使用";

}

$("#divId").css({ color:

cor});

$("#divId").html(mes);});

}); });

action="servlet/CheckLoginName" >

用户名：

type="text" id= "loginName" name = "loginName"

/>

id="divId">

密码：

type="password" name =

"loginPass"/>

---------------------------------servlet代码----------------------------------------------------

import java.io.IOException;

import java.net.URLDecoder;

import java.net.URLEncoder;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class CheckLoginName2 extends HttpServlet {

@Override

protected void doGet(HttpServletRequest req,

HttpServletResponse resp)

throws

ServletException, IOException {

this.doPost(req, resp);

}

@Override

protected void doPost(HttpServletRequest req,

HttpServletResponse resp)

throws

ServletException, IOException {

req.setCharacterEncoding("utf-8");

//js中使用encodeURI(encodeURI())传值在java中药使用URLDecoder.decode解析;

String name =

URLDecoder.decode(req.getParameter("name"), "utf-8");

System.out.println(name);

//防止浏览器缓存、

resp.setContentType("text/html");

//resp.setContentType("text/xml");

resp.setHeader("Cache-Control","no-store");

resp.setHeader("Pragma","no-cache");

resp.setDateHeader("Expires",

0);

//查看数据库是否存在数据,修改这里

resp.getWriter().write("false");

}

}