public function render($html = null) {
		$separator = $this->getSeparator();
		$result    = '';
		
		if ($this->_colgroup !== null) {
			$result .= $separator . $this->_colgroup->render();
		}
		
		if ($this->_head !== null) {
			$result .= $separator . $this->_head->render();
		}
		
		if ($this->_body !== null) {
			$result .= $separator . $this->_body->render();
		}
		
		if ($this->_foot !== null) {
			$result .= $separator . $this->_foot->render();
		}
		
		return parent::render($result . $separator);
	}