/** * Append childnode to document * @param ZXmlTag|DOMNode|mixed $a_tag * @return ZXmlDocument */ public function &append($a_tag) { if ($a_tag instanceof ZXmlTag) { $this->m_document->appendChild($a_tag->node()); } else { if ($a_tag instanceof DOMNode) { $this->m_document->appendChild($a_tag); } } return $this; }