function getCategoryChilds($catid, $clear = true) {

        static $array = array();
        if ($clear)
            $array = array();
        $user = &JFactory::getUser();
        $aid = (int) $user->get('aid');
        $catid = (int) $catid;
        $db = &JFactory::getDBO();
        $query = "SELECT * FROM #__k2_categories WHERE parent={$catid} AND published=1 AND trash=0 AND access<={$aid} ORDER BY ordering ";
        $db->setQuery($query);
        $rows = $db->loadObjectList();

        foreach ($rows as $row) {
            array_push($array, $row->id);
            if (K2ModelItemlist::hasChilds($row->id)) {
                K2ModelItemlist::getCategoryChilds($row->id,false);
            }
        }
        return $array;
    }