private function protectTags(HtmlDomParser $dom): HtmlDomParser
    {
        // init
        $counter = 0;

        foreach ($dom->find('script, style') as $element) {

            // skip external links
            if ($element->tag === 'script' || $element->tag === 'style') {
                $attributes = $element->getAllAttributes();
                if (isset($attributes['src'])) {
                    continue;
                }
            }

            $this->protectedChildNodes[$counter] = $element->text();
            $element->getNode()->nodeValue = '<' . $this->protectedChildNodesHelper . ' data-' . $this->protectedChildNodesHelper . '="' . $counter . '"></' . $this->protectedChildNodesHelper . '>';

            ++$counter;
        }

        foreach ($dom->find('code, nocompress') as $element) {
            if ($element->isRemoved()) {
                continue;
            }

            $this->protectedChildNodes[$counter] = $element->parentNode()->innerHtml();
            $element->getNode()->parentNode->nodeValue = '<' . $this->protectedChildNodesHelper . ' data-' . $this->protectedChildNodesHelper . '="' . $counter . '"></' . $this->protectedChildNodesHelper . '>';

            ++$counter;
        }

        foreach ($dom->find('//comment()') as $element) {
            $text = $element->text();

            // skip normal comments
            if (!$this->isConditionalComment($text)) {
                continue;
            }

            $this->protectedChildNodes[$counter] = '<!--' . $text . '-->';

            /* @var $node \DOMComment */
            $node = $element->getNode();
            $child = new \DOMText('<' . $this->protectedChildNodesHelper . ' data-' . $this->protectedChildNodesHelper . '="' . $counter . '"></' . $this->protectedChildNodesHelper . '>');
            /** @noinspection UnusedFunctionResultInspection */
            $element->getNode()->parentNode->replaceChild($child, $node);

            ++$counter;
        }

        return $dom;
    }