PHP學習-驗證用戶名密碼

登陸頁：login.php

 1 <?php
 2 //登陸
 3 if(!isset($_POST['submit'])){exit('非法訪問!');}
 4 $username = $_POST['adname'];
 5 $password = $_POST['adpass'];
 6 //包含數據庫鏈接文件
 7 include('conn.php');
 8 //檢測用戶名及密碼是否正確
 9 $check_query = mysql_query("select * from admin where ad_name='$username' and ad_code='$password' limit 1");
10 if($result = mysql_fetch_array($check_query)){
11     //登陸成功
12     session_start();
13     $_SESSION['username'] = $username;
14     $_SESSION['userid'] = $result['ad_id'];
15     echo $username,' 歡迎你！進入 <a href="my.php">用戶中心</a><br />';
16     echo '點擊此處 <a href="login.html">註銷</a> 登陸！<br />';
17     exit;
18 } else {
19     exit('登陸失敗！點擊此處 <a href="javascript:history.back(-1);">返回</a> 重試');
20 }
21 //註銷登陸
22 if($_GET['action'] == "logout"){
23     unset($_SESSION['userid']);
24     unset($_SESSION['username']);
25     echo '註銷登陸成功！點擊此處 <a href="login.html">登陸</a>';
26     exit;
27 }
28 ?>

$_POST["a"]：獲取post提交的數據a的值

mysql_query("select * from admin where ad_name='$username' and ad_code='$password' limit 1");執行一條MySQL查詢

mysql_fetch_array($check_query)：獲取根據如上數據表查詢的一行信息