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Correction status：Uncorrected
Teacher's comments：
Collection
Collection
<?php
// 防止重复登录
if (isset($_COOKIE['username']) && $_COOKIE['username'] === 'admin') {
echo '<script>alert("您已经登录,请不要重复登录");location.assign("admin.php");</script>';
die;
}
?>
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>用户登录</title>
</head>
<body>
<h3>用户登录</h3>
<form action="check.php" method="post" onsubmit="return isEmpty()">
<p>
<label for="email">邮箱:</label>
<input type="email" name="email" id="email">
</p>
<p>
<label for="password">密码:</label>
<input type="password" name="password" id="password">
</p>
<p>
<button>提交</button>
</p>
</form>
<script>
// onsubmit: 表单提交前进行验证, 默认返回true
// 非空验证函数 isEmpty 判断是否为空 ，isSet()判断是否有值
function isEmpty() {
var email = document.getElementById('email').value;
var password = document.getElementById('password').value;
if (email.length === 0 || password.length === 0 ) {
alert('邮箱或密码不能为空');
return false;
}
}
</script>
</body>
</html>点击 "运行实例" 按钮查看在线实例
<?php check.php- 判断用户数据是否正确
// 防止重复登录
if (isset($_COOKIE['username']) && $_COOKIE['username'] === 'admin') {
echo '<script>alert("您已经登录,请不要重复登录");location.assign("admin.php");</script>';
die;
}
//print_r($_POST);
// 连接数据库
require __DIR__ . '/inc/connect.php';
$email = $_POST['email'];
$password = sha1($_POST['password']);
// 到用户表user中进行验证
$sql = 'SELECT * FROM `user` WHERE `email` = :email AND `password` = :password';
$stmt = $pdo->prepare($sql);
//把获取到的变量赋值给数据库查询变量进行查询(或者说互相绑定)
$stmt->execute([':email'=>$email,':password'=>$password]);
// fetch(): 成功返回数组,失败返回false
$user = $stmt->fetch(PDO::FETCH_ASSOC);
if ( $user===false) {
// 登录失败
echo '<script>alert("登陆失败,请检查");history.back();</script>';
die; // 终止当前脚本
}
// 登录成功,将用户信息写入cookie
setcookie('username', $user['username']);
setcookie('password', $user['password']);
echo '<script>alert("登录成功");location.assign("admin.php");</script>';点击 "运行实例" 按钮查看在线实例
<?php
// 禁止非授权用户访问
// 连接数据库
require __DIR__ . '/inc/connect.php';
$sql = 'SELECT * FROM `user` WHERE `username`=:name';
$stmt =$pdo-> prepare($sql);
if(isset($_COOKIE['username'])){
$stmt->execute([':name'=>$_COOKIE['username']]);
$user = $stmt->fetchAll(PDO::FETCH_ASSOC);
}
//echo '<pre>' . print_r($user,true);
if (isset($_COOKIE['username']) && $_COOKIE['username'] === $user[0]['username']):
?>
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>后台首页</title>
</head>
<body>
<h1>后页首页</h1>
<p>欢迎:
<?php echo $_COOKIE['username']; ?>
</p>
<p><a href="logout.php">退出</a></p>
</body>
</html>
<?php else: ?>
<script>alert("请登录");location.assign('login.php');</script>
<?php endif; ?>点击 "运行实例" 按钮查看在线实例
<?php
// 必须在已登录的情况下,才允许退出
if (isset($_COOKIE['username']) && $_COOKIE['username'] === 'admin') {
setcookie('username', null, time()-3600);
echo '<script>alert("退出成功");location.href="login.php";</script>';
} else {
echo '<script>alert("请先登录");location.assign("login.php");</script>';
}点击 "运行实例" 按钮查看在线实例