public function trackPage($page = null, $title = null, $type = self::TYPE_PAGEVIEW)
	{
		if (!defined('self::TYPE_'. strtoupper($type))) {
			throw new AnalyticsArgumentException('Type variable can\'t be of this type.');
		}

		$item = "ga('send', 'pageview');";

		if ($page !== null || $title !== null) {
			$page = ($page === null ? "window.location.href" : "'{$page}'");
			$title = ($title === null ? "document.title" : "'{$title}'");
			$item = "ga('send', { 'hitType': '{$type}', 'page': {$page}, 'title': {$title} });";
		}

		$this->addItem($item);
	}