$user=$_REQUEST['user'];

    $app_id = "2342084241";

	//?i=$user
     $canvas_page = "http://apps.facebook.com/pirates/";

     $message = "You have been invited to play Pirates!";

     $requests_url = "http://www.facebook.com/dialog/apprequests?app_id="
            . $app_id . "&redirect_uri=" . urlencode($canvas_page)
            . "&message=" . $message;

     if (empty($_REQUEST["request_ids"])) {
        echo("<script> top.location.href='" . $requests_url . "'</script>");
     } else {
        echo "Request Ids: ";
        print_r($_REQUEST["request_ids"]);
     }