 		/** Close the current Facebook session and delete the token from the cache. */
 		public function closeSessionAndClearTokenInformation() : void
 		{
+			if (!isSupported) return;
+			
 			_context.call('closeSessionAndClearTokenInformation');
 		}
 		

		 */
		public function get expirationTimestamp() : Number
		{
			return _context.call('getExpirationTimestamp') as Number;
		}
		

		private var _requestCallbacks : Object = {};
		
		private function openSessionWithPermissionsOfType( permissions : Array, type : String, callback : Function = null ) : void
		{
			if (!isSupported) return;
			
			_openSessionCallback = callback;
			_context.call('openSessionWithPermissions', permissions, type);
		}
		
		private function reauthorizeSessionWithPermissionsOfType( permissions : Array, type : String, callback : Function = null ) : void
		{
			if (!isSupported) return;
			
			_reauthorizeSessionCallback = callback;
			_context.call('reauthorizeSessionWithPermissions', permissions, type);
		}
