function login($usr,$pwd) {
    global $conn;
    $username = htmlspecialchars($usr);
    $password = md5(htmlspecialchars($pwd));

    $check_q = $conn->query("SELECT * FROM `users` WHERE `username` = '$username' AND `password` = '$password'");
    $check = $check_q->num_rows;
    if($check == 1) {
        return 1;
    } else {
        return 0;
    }
    return 0;
}