when change browser tabs game freezes

I made an idle game(link http://www.kongregate.com/games/jckTaiwan/enemy-factory).

Some players have complains about the game freezed when change browser tab. "When most people play idle games they like to change browser tabs to look at or play something else, leaving the game to play in the background and then go back to buy upgrades after awhile. " is from a player.

Is it possible to keep the game continue after browser tab changed?

Thanks.

C2 doesn't support making games that run in the background..

When unfocused the game suspends..

Using the "on resumed" event you could however update the game to what should have happened..

Thanks for your answer.