private function chromeWithMajorVersion($userAgent) {
		$start_idx = strpos($userAgent, 'Chrome');
		$end_idx = strpos($userAgent, '.', $start_idx);
		if ($end_idx === false) {
			return substr($userAgent, $start_idx);
		} else {
			return substr($userAgent, $start_idx, ($end_idx - $start_idx));
		}
	}