FluentDOM\Query::append PHP Method

    public function append($content)
    {
        if (empty($this->_nodes) && $this->_useDocumentContext && !isset($this->getDocument()->documentElement)) {
            if ($callback = Constraints::isCallable($content)) {
                $contentNode = $this->build()->getContentElement($callback(NULL, 0, ''));
            } else {
                $contentNode = $this->build()->getContentElement($content);
            }
            return $this->spawn($this->getDocument()->appendChild($contentNode));
        } else {
            return $this->applyToSpawn($this->_nodes, $content, function ($targetNode, $contentNodes) {
                return $this->modify($targetNode)->appendChildren($contentNodes);
            });
        }
    }