function &addDoctype($dtd, &$offset = null) {
	#php5e
		return $this->addChild(new $this->childClass_Doctype($this, $dtd), $offset);
	}
function &addDoctype($dtd, &$offset = null) {
	#php5e
		return $this->addChild(new $this->childClass_Doctype($this, $dtd), $offset);
	}
#php5