Ajax技术--检查用户名是否唯一

来源：互联网发布：cnc编程上班时间是怎样编辑：程序博客网时间：2024/05/16 04:34

index.jsp界面：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><style>    #div1 {display: none;width: 100px;background: red;}    </style><script>  window.onload = function(){    var oBtn = document.getElementById("btn1");    var oUsername = document.getElementsByName("username")[0];        oBtn.onclick = function(){      checkUser(oUsername.value);    }        function checkUser(username){       if(username == ""){         alert ("请输入用户名");       }else {         createRequest("checkUser.jsp?user="+username);       }    }        function createRequest(url){       var request = null;       if(window.XMLHttpRequest){       request = new XMLHttpRequest()       }       else if(window.ActiveXObject){       try{       request = new ActiveXObject("Msxml.XMLHTTP");       }catch(e){       try{       request = new ActiveXObject("Microsoft.XMLHTTP");       }catch(e){       //TODO handle the exception       }       }       }              if(!request){       alert('不能创建XMLHttpRequest实例');       return false;       }       request.open('get',url,true);       request.send(null);       request.onreadystatechange = function(){       if(request.readyState == 4){       if(request.status == 200){        document.getElementById("div1").innerHTML = request.responseText ;       document.getElementById("div1").style.display = 'block';       }       }       };     }  }</script>  </head>    <body>    <form method = "get" action = "" name = "form1">    用户名：<input name = "username" type = "text" size ="32"><br><br>    <input name = "btn" type = "button" value = "检测"  id="btn1">    </form>    <div id ="div1"></div>  </body></html>

checkUser.jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><%String [] userList = {"明日科技","mr","mrsoft","wgh"};String user = new String (request.getParameter("user").getBytes("ISO-8859-1"),"utf-8");Arrays.sort(userList); //对数组进行排序int result = Arrays.binarySearch(userList,user);  //若存在则返回索引值，否则返回-1System.out.println(result);if(result > -1){  out.print(result+":很抱歉，该用户名已经被注册");}else {  out.print(result+":恭喜您，该用户名没有被注册");} %>

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