How do I have an object that has an increasing variable?

I want a simple increasing variable which would be easy, but I want it to keep increasing even after the game is closed. For example a tree has 2 apples and after the game is closed and one day has passed the game is continued and the tree has 3 apples.

This is very difficult and I have no clue so I'm helpless.

Thank you an good day.

Maybe you could save on Webstorage the date (using Javascript, I guess?) when you closed the game. When you open it, load the Webstorage key value and check again the date. Compare and do whatever you want.

Check this plugin:

Thanks!