Symfony\Component\DomCrawler\Crawler::filterRelativeXPath PHP Method

    private function filterRelativeXPath($xpath)
    {
        $prefixes = $this->findNamespacePrefixes($xpath);
        $crawler = $this->createSubCrawler(null);
        foreach ($this->nodes as $node) {
            $domxpath = $this->createDOMXPath($node->ownerDocument, $prefixes);
            $crawler->add($domxpath->query($xpath, $node));
        }
        return $crawler;
    }