| 适合人群：Ajax和jQuery入门 采用Ajax实现用户名验证 使用jQuery给出提示信息 用户注册的时候，使用Ajax实现检测用户名是否已经被注册过，很多细节没有实现，给大家做个简单普及。 <%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>用户注册页面</title><script src="https://libs.baidu.com/jquery/1.8.3/jquery.min.js"></script><script type="text/javascript"> var xmlHttp; function createXMLHttpRequest(){ if(window.XMLHttpRequest){ xmlHttp = new XMLHttpRequest(); }else if(window.ActiveXObject){ xmlHttp = new ActiveXObject("Microsoft.XMLHttp"); } } function validate(account){ createXMLHttpRequest(); xmlHttp.open("Get","ValidateServlet?account="+account,true); xmlHttp.onreadystatechange = callback; xmlHttp.send(null); } function callback(){ if(xmlHttp.readyState==4){ if(xmlHttp.status==200){ var text = xmlHttp.responseText; if(text=="true"){ //document.getElementById("msg").innerHTML = "该手机号已经被注册过"; $("#msg").text("该手机号已经被注册"); $("#sub").attr("disabled","true");//添加disabled属性，让按钮不可用 }else{ //document.getElementById("msg").innerHTML = ""; $("#msg").text(""); $("#sub").removeAttr("disabled");//移除disabled属性，让按钮可用 } }else{ alert("请求失败，错误码="+xmlHttp.status); } } } function checkInfo(){ var account = $("#account").val(); var pwd1 = $("#pwd1").val(); var pwd2 = $("#pwd2").val(); if(account==""||account==null){ $("#msg").text("账号不能为空"); $("#sub").attr("disabled","true"); return false; } if(pwd1==""||pwd1==null||pwd2==""||pwd2==null||pwd1!=pwd2){ $("#info").text("密码不能为空或者两次密码不一致"); $("#sub").attr("disabled","true"); return false; } $("#msg").text(""); $("#info").text(""); $("#sub").removeAttr("disabled"); } function submit(){ checkInfo(); $("#reg").submit(); } </script></head><body><form id="reg" name="reg" action="RegisterServlet" method="post">账号：<input type="text" name="account" id="account" onblur="validate(this.value);"><span id="msg" style="color:red">请输入手机号</span><br>密码：<input type="password" id="pwd1" name="password1" onblur="checkInfo();"><br>确认密码：<input type="password" id="pwd2" name="password2" onblur="checkInfo();"><span id="info" style="color:red"></span><br><input type="button" id="sub" value="提交" onclick="submit();"></form></body></html>下面是ValidateServlet模拟实现，没有做真正的数据库表数据检测，大家自行完成。 package com.ambow.servlet; import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; @WebServlet("/ValidateServlet")public class ValidateServlet extends HttpServlet { private static final long serialVersionUID = 1L; public ValidateServlet() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter pw = response.getWriter(); String account = request.getParameter("account"); System.out.println("account"+account); if("123".equals(account)) { pw.print("true"); }else { pw.print("false"); } } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }}到此这篇关于利用Ajax检测用户名是否被占用的文章就介绍到这了,更多相关Ajax检测用户名被占用内容请搜索51zixue.net以前的文章或继续浏览下面的相关文章希望大家以后多多支持51zixue.net！
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