function submitmyform(form) {
    jQuery.fancybox({ href: 'https://securereservations.eu/check_availability.aspx?logisid=517&taal=' + jQuery("#lang_cubilis", form).val() + '&startdatum=' + jQuery("#start_TextBox", form).val() + '&einddatum=' + jQuery("#end_TextBox", form).val(), type: 'iframe', width: 500, height: 550 });
    return false;
}