diff --git a/framework/yii/web/Session.php b/framework/yii/web/Session.php
index b3be392..86f3506 100644
--- a/framework/yii/web/Session.php
+++ b/framework/yii/web/Session.php
@@ -82,6 +82,7 @@ class Session extends Component implements \IteratorAggregate, \ArrayAccess, \Co
 	public $flashVar = '__flash';
 	/**
 	 * @var array parameter-value pairs to override default session cookie parameters that are used for session_set_cookie_params() function
+	 * Array may have the following possible keys: 'lifetime', 'path', 'domain', 'secure', 'httpOnly'
 	 * @see http://www.php.net/manual/en/function.session-set-cookie-params.php
 	 */
 	private $_cookieParams = ['httpOnly' => true];