<?php
session_start();
// Check if the form is submitted
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // Check login credentials
    $username = "admin";
    $password = "1234";
    if ($_POST["username"] == $username && $_POST["password"] == $password) {
        // Authentication successful
        $_SESSION["loggedin"] = true;
        header("Location: test.php");
        exit();
    } else {
        // Authentication failed
        $error = "Invalid username or password";
    }
}
?>