Language Select (select.php)

<?php
error_reporting(E_ALL ^ E_NOTICE);

define('COOKIE_TIMEOUT_LENGTH',180/*days*/ * 24 /*hours*/ * 60 /*min*/ * 60/*sec*/);

$mode = $_GET['mode'];

switch (strtolower($mode)) {

    case 'set' :
        $language = strtolower($_GET['language']);
        if ('dansk' == $language) {
            setcookie('language', 'dansk', time() + COOKIE_TIMEOUT_LENGTH);
            header("Location: ".$_SERVER['PHP_SELF'].'?mode=testcookie');
            exit;
        } elseif ('english' == $language) {
            setcookie('language', 'english', time() + COOKIE_TIMEOUT_LENGTH);
            header("Location: ".$_SERVER['PHP_SELF'].'?mode=testcookie');
            exit;
        }
        break;

    case 'testcookie' :
        $cookie_warning = (!isset($_COOKIE['language']));
        break;
}


if (isset($_COOKIE['language'])) {
    switch ($_COOKIE['language']) {
        case 'dansk' :
            header("Location: /");
            exit;
            break;
        case 'english' :
            header("Location: /en");
            exit;
            break;
    }
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

[ ... HTML .... ]