An additional way to archaeous-suggestion —> save a state/flag-value into your DB (for example boolean-value —> TRUE / FALSE).
Once you disappeared your BOX, you set the value to true or vice-versa, like you want and save it in a field of your DB.
Everytime you open the site with the mentioned BOX, you first tcheck the boolean-value in your DB. I think the rest of story is clear enough…