public function getTagById( $id, $throwException = TRUE )
	{
		$xpath	= new DomXPath( $this->document );
		$query	= "//*[@id = '$id']";
		$tags	= $this->getTagsByXPath( $query );
		if( $tags )
			return $tags[0];
		if( $throwException )
			throw new RuntimeException( 'No Tag with ID "'.$id.'" found.' );
		return NULL;
	}