php and javascript page reditect

php and javascript page reditect.php

$url = "index.php";
redirect($url);

function redirect($url) {
    if (headers_sent()) {
        die('<script type="text/javascript">window.location.href="' . $url . '";</script>');
    } else {
        header('Location: ' . $url);
        die();
    }
}