Why would you want to save data like 'id' or 'product quantity' when the user's not there anymore?
Sessions are destroyed when the browser window closes, as you know.
If you want to know what people were doing before they closed the window, save the actions to variables and put them in a DB (while the user's still online). This is the only way to actually keep records of what people WERE doing, before they left.
thefisherman