public static function find_all_headers($elements, &$header_array) { foreach ($elements as $e) { if (substr($e->tag, 0, 1) == "h" and intval(substr($e->tag, 1)) != 0) { array_push($header_array, $e); } BasicChecks::find_all_headers($e->children(), $header_array); } return $header_array; }