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JavaScript学习4---ajax的使用

发布时间:2016-12-3 12:41:17 编辑:www.fx114.net 分享查询网我要评论
本篇文章主要介绍了"JavaScript学习4---ajax的使用",主要涉及到JavaScript学习4---ajax的使用方面的内容,对于JavaScript学习4---ajax的使用感兴趣的同学可以参考一下。

function getXMLHttpRequest(){         //IE浏览器    var client = getXMLHttpRequestFromIE();    if(client == null){        //非IE浏览器        client = new XMLHttpRequest();    }        return client;} function getXMLHttpRequestFromIE(){    var namePrefixes = ["Msxml3", "Msxml2", "Msxml", "Microsoft"];    for(var i = 0; i < namePrefixes.length; i++){        var name = namePrefixes[i] + ".XMLHTTP";        try{          return new ActiveXObject(name);        }catch(e){        }    }        return null;}   jsp文件: <%@ page  pageEncoding="gbk"%> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"         "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head>  <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/style/style.css"></link>  <style type="text/css">        #content div{     margin: 10px 0px;   }      div.submit{     text-align:center;   }      label{     width:80px;     display:block;     float:left;   }      fieldset{      width:300px;      margin:auto;      margin-top:20px;      display:block;   }      fieldset select{     width:120px;   }      fieldset input{     width:120px;   }       </style>  <title>登录</title>  <script type="text/javascript" src="${pageContext.request.contextPath}/js/client.js"></script>  <script type="text/javascript">        var client = getXMLHttpRequest();                function login(form){                        var username = form.username.value;            var password = form.password.value;                        var requestURL = "${pageContext.request.contextPath}/login.do?username=" + username + "&password=" + password;            requestURL += "&time=" + new Date().getTime();                        client.open("GET", requestURL, true);            client.onreadystatechange = function(){                if(client.readyState == 4){                    if(client.status == 200){                        var result = parseInt(client.responseText);                        if(result == 0){                               document.getElementById("message").innerHTML = "用户不存在或密码不正确!" ;                        }else{                          window.location = "${pageContext.request.contextPath}/memberCenter.jsp";                        }                    }                }            }            client.send(null);        }                function clearMessage(){            document.getElementById("message").innerHTML = "";        }  </script></head><body><div id="container">  <div id="header">    <ul>      <li><a href="#">帮助</a></li>    </ul>  </div>  <div id="menu">    <ul>      <li><a href="index.html">首页</a></li>      <li><a href="roomPrice.html">设施与价格</a></li>      <li><a href="memberCenter.html">会员中心</a></li>    </ul>  </div>  <div id="content">  <form>    <fieldset>      <legend>登录信息</legend>      <div>        <label for="username">用户名</label>        <input type="text" name="username" id="username"  onfocus="clearMessage()"/>      </div>      <div>        <label for="password">密码</label>        <input type="text" name="password" id="password"   onfocus="clearMessage()"/>      </div>    </fieldset>    <div id="message"></div>    <div class="submit">      <input type="button" value="登录" onclick="login(this.form)"/>      <p>如果您还没有注册,请<a href="${pageContext.request.contextPath}/register.jsp">点击这里注册</a>成为会员。</p>    </div>  </form>  </div>  <hr />  <div id="footer">    <p>本系统做为Java Web教学设计使用。未经允许,不得做为它用,版权所有Allan<br />联系方式:[email protected]</p>  </div></div></body></html>     servlet 代码   package action; 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;import javax.servlet.http.HttpSession; import util.RequestUtil;import biz.Member;import biz.MemberBiz; public class ActionServlet extends HttpServlet {  public void doGet(HttpServletRequest request, HttpServletResponse response)   throws ServletException, IOException {  String path = request.getServletPath();  path = path.substring(0, path.indexOf("."));  if (path.equals("/register")) {   register(request, response);  } else if (path.equals("/login")) {   login(request, response);  } else if (path.equals("/validateusername")) {   validateUsername(request, response);  } }  public void doPost(HttpServletRequest request, HttpServletResponse response)   throws ServletException, IOException {  doGet(request, response); }  public void register(HttpServletRequest request,   HttpServletResponse response) throws ServletException, IOException {  Member member = new Member();  RequestUtil.setProperties(request, member);  MemberBiz memberBiz = new MemberBiz();  Member m = memberBiz.find(member.getUsername());  if (m != null) {   request.setAttribute("message", "username " + m.getUsername()     + " has already existed.");   getServletContext().getRequestDispatcher("/register.jsp").forward(     request, response);  } else {   memberBiz.add(member);   getServletContext().getRequestDispatcher("/success.jsp").forward(     request, response);  } }  public void validateUsername(HttpServletRequest request,   HttpServletResponse response) throws ServletException, IOException {  response.setContentType("text/plain;charset=gbk");  PrintWriter out = response.getWriter();   String username = request.getParameter("username");  MemberBiz memberBiz = new MemberBiz();  Member m = memberBiz.find(username);  if (m == null) {   out.println(0);  } else {   out.println(1);  }  out.close(); }  public void login(HttpServletRequest request, HttpServletResponse response)   throws ServletException, IOException {  response.setContentType("text/plain;charset=gbk");  PrintWriter out = response.getWriter();   String username = request.getParameter("username");  String password = request.getParameter("password");  MemberBiz memberBiz = new MemberBiz();  Member m = memberBiz.find(username, password);  if(m == null){   out.println(0);  }else{   HttpSession session = request.getSession();   session.setAttribute("user", m);   out.println(1);  }  out.close(); } }        

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