QueryPath\CSS\DOMTraverser::initialMatchOnElementNS PHP Method

    protected function initialMatchOnElementNS($selector, $matches)
    {
        $ns = $selector->ns;
        $elements = $this->initialMatchOnElement($selector, $matches);
        // "any namespace" matches anything.
        if ($ns == '*') {
            return $elements;
        }
        // Loop through and make a list of items that need to be filtered
        // out, then filter them. This is required b/c ObjectStorage iterates
        // wrongly when an item is detached in an access loop.
        $detach = array();
        foreach ($elements as $node) {
            // This lookup must be done PER NODE.
            $nsuri = $node->lookupNamespaceURI($ns);
            if (empty($nsuri) || $node->namespaceURI != $nsuri) {
                $detach[] = $node;
            }
        }
        foreach ($detach as $rem) {
            $elements->detach($rem);
        }
        $selector->ns = null;
        return $elements;
    }