<?php session_start(); //注销登录 if($_GET['action'] == "logout"){ unset($_SESSION['userid']); unset($_SESSION['username']); echo '注销登录成功!点击此处 <a href="login.html">登录</a>'; exit; } //登录 if(!isset($_POST['submit'])){ exit('非法访问!'); } $username = htmlspecialchars($_POST['username']); $password = MD5($_POST['password']); //包含数据库连接文件 include('conn.php'); //检测用户名及密码是否正确 $check_query = mysql_query("select uid from user where username='$username' and password='$password' limit 1"); if($result = mysql_fetch_array($check_query)){ //登录成功 $_SESSION['username'] = $username; $_SESSION['userid'] = $result['uid']; echo $username,' 欢迎你!进入 <a href="my.php">用户中心</a><br />'; echo '点击此处 <a href="login.php?action=logout">注销</a> 登录!<br />'; exit; } else { exit('登录失败!点击此处 <a href="javascript:history.back(-1);">返回</a> 重试'); } ?>