protected function getDocument( $content, $url )
	{
		$doc = new DOMDocument();
		ob_start();
		if( !@$doc->loadHTML( $content ) )
		{
			$content	= ob_get_clean();
			if( $content )
				$this->errors[$url]	= $content;
			throw new RuntimeException( 'Error reading HTML.' );
		}
		ob_end_clean();
		return $doc;
	}