在PHP登录页面中使用cookie

我正在创建一个用PHP（显然还有MySQL）登录的表单。这是PHP代码：

<?php
$host = 'localhost';
$db_user = 'root';
$db_password = '';
$db_name = 'learningsql';

$username = stripslashes($_POST['username']);
$password = stripslashes($_POST['password']);

if (strlen($username) < 1 || strlen($password) < 1){
    echo "Username or password incorrect";
} else {
    $username = trim(filter_var($_POST['username'], FILTER_SANITIZE_STRING));
    $password = trim(filter_var($_POST['password'], FILTER_SANITIZE_STRING));
    $hash = hash("sha512",$username. $password);
    $connection = mysqli_connect($host, $db_user, $db_password);
    $db = mysqli_select_db($connection, $db_name);
    $result = mysqli_query("SELECT * FROM utenti WHERE username = '$username' AND password = '$hash'");
    if(mysqli_num_rows($result)==0{
        die("Username or password incorrect");
    } else{
        $_SESSION['loggedin']=1;
        $user = mysqli_fetch_array($result);
        header("location:loggato.php");

    }
}
?>

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PHP会话存储一个cookie以启用会话。使用函数

session\u start（）

启动会话（duhh），会话将设置一个名为PHPSESSID的cookie。使用一些开发工具在浏览器中检查它。

stripslashes？您需要将PHP版本升级到石器时代的版本。

<?php
session_start();
if(isset($_SESSION['loggedin']))
    header('location:loggato.html');
?>