PHP學習-驗證用戶名密碼

登錄頁：login.php

<?php
//登錄
if(!isset($_POST['submit'])){exit('非法訪問!');}
$username = $_POST['adname'];
$password = $_POST['adpass'];
//包含數據庫連接文件
include('conn.php');
//檢測用戶名及密碼是否正確
$check_query = mysql_query("select * from admin where ad_name='$username' and ad_code='$password' limit 1");
if($result = mysql_fetch_array($check_query)){
    //登錄成功
    session_start();
    $_SESSION['username'] = $username;
    $_SESSION['userid'] = $result['ad_id'];
    echo $username,' 歡迎你！進入 <a href="my.php">用戶中心</a><br />';
    echo '點擊此處 <a href="login.html">注銷</a> 登錄！<br />';
    exit;
} else {
    exit('登錄失敗！點擊此處 <a href="javascript:history.back(-1);">返回</a> 重試');
}
//注銷登錄
if($_GET['action'] == "logout"){
    unset($_SESSION['userid']);
    unset($_SESSION['username']);
    echo '注銷登錄成功！點擊此處 <a href="login.html">登錄</a>';
    exit;
}
?>

$_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