PHP如何通过AJAX方式实现登录功能

本文实例讲述了Ajax+PHP+MySQL登陆示例。分享给大家供大家参考。具体如下：
运行效果截图如下：

具体代码如下：

1 login.php
登录界面中,javascript脚本用ajax方式异步请求dologin.php,dologin.php负责用户信息验证(包括验证码,php生成验证码可以自行搜索).登录界面的代码如下:

<?php session_start();?>
<!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>
 <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
 <title>login</title>
 <link rel="stylesheet" type="text/css" href="CSS/login.css" />
 <script src="JS/ajaxhelper.js" type="text/javascript"></script>
 <script src="JS/jquery-1.3.2.min.js" type="text/javascript"></script>
 <script type="text/javascript">
  function chkForm() {
   if (m$('username').value == "") {

    alert('用户名不能为空.');
    m$('username').focus();
    return false;

   }
   if (m$('password').value == "") {

    alert('密码不能为空.');
    m$('password').focus();
    return false;

   }
   if (m$('password').value != "" && m$('username').value != "") {

    var xmlhttp = createRequest();
    if (xmlhttp) {
     m$('loading').innerHTML = "<font color='red'>loading...</font>";
     var username = m$('username').value;
     var pwd = m$('password').value;
     var code = m$('txtCode').value;
     var url = "dologin.php";
     xmlhttp.open("POST", url, true);
     xmlhttp.onreadystatechange = ValidateResult;
     xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
     xmlhttp.send("username=" + escape(username) + "&password=" + escape(pwd) + "&code=" + escape(code));

    } else {
     alert('xmlHttp创建失败.');

    }

    function ValidateResult() {
     if (xmlhttp.readyState == 4) {
      if (xmlhttp.status == 200) {
       if (xmlhttp.responseText != "") {

        //window.alert(xmlhttp.responseText);
        var obj = eval("(" + xmlhttp.responseText + ")");
        if (obj.result == true) {
         alert("提示:" + obj.info);
         window.location = 'index.php';

        } else {
         alert("错误:" + obj.info);

        }
       } else {
        window.alert("从服务器获取失败");

        window.location.reload();
       }
       m$('loading').innerHTML = "";
      }
     }

    }


   }

  }

  function m$(id) {
   return document.getElementById(id);
  }

  function changeCode() {
   var xmlhttp = createRequest();
   if (xmlhttp) {
    m$('loading').innerHTML = "<font color='red'>loading...</font>";
    var dt = new Date().getTime();
    // alert(dt);
    var url = "function/imagecode.php?dummay" + escape(dt);
    xmlhttp.open("GET", url, true);
    xmlhttp.onreadystatechange = ValidateResult;
    xmlhttp.send(null);

   } else {
    alert('xmlHttp创建失败.');

   }

   function ValidateResult() {
    if (xmlhttp.readyState == 4) {
     if (xmlhttp.status == 200) {
      var dt = new Date().getTime();
      var url = "function/imagecode.php?dummay" + escape(dt);
      m$('imgCode').src = "function/imagecode.php?dummay" + escape(dt);
      m$('loading').innerHTML = "";
     }
    }

   }
  }

  function showTool() {
   $('#divToolTip').css("display", "block");
  }

  function hideTool() {
   $('#divToolTip').css("display", "none");
  }
  window.onload = initPage;

  function initPage() {
   $('#divToolTip').css("display", "none");
  }
 </script>
 </head>
 <body>
 <div style="background-color:#2A3F55; height:80px;">
  
 </div>
 <div style="min-height:500px;">
  
  <div class="left">
  
  <div style="margin:120px auto auto auto; height:300px; text-align:left">
   <div style="font-size:26px;color:#2A3F55; text-align:center;">Ajax PHP Demo System
   <img src="Images/appstorm-icon.png" alt="appcation storm image" style="position:relative;top:-18px; left:-12px;         vertical-align:middle; text-align:center;font-size:10px; width:65px; height:46px;"/>
   </div>
   <br/>
   <hr style="border:dashed thin #2A3F55;width:70%; text-align:center;"/>
   <div style="font-size:13px;color:#999999; margin:20px auto 0 auto; padding-left:200px;">
   Author:<a href="#" onmousemove="showTool();" onmouseout="hideTool();">wangming</a>
   </div>
   <div style="font-size:13px;color:#999999;margin:20px auto auto auto; padding-left:200px;">DateTime:2009-9-1</div>
   <div style="font-size:13px;color:#999999;margin:20px auto auto auto; padding-left:200px;">Version:1.0.0</div>
   <div style="font-size:13px;color:#999999;margin:20px auto auto auto; padding-left:200px;">Email:wangmingemail@163.com     </div>
   <div id="divToolTip">
   <img src="Images/ming.jpg" height="86px;"/>
   <span class="authordes">
    <br/>
    姓名:wangming<br/>
    电商06-2<br/>
   <(UU}Р}ё}Ё}щ}э}}щЁZЁЁЁи4(4(4(fW^!CV6eME3{:UIN74(bF+'!CkZ?{:fW*ro疒j惚r'&*

PHP如何通过AJAX方式实现登录功能

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