what data saved in cookie to identify anonymous user

I have an e-shopping site. I want keep anonymous user ord开发者_StackOverflow社区ers and if the browser is closed, When user come back to my site, I show user orders, Now what data I should save in cookie and use it to show user orders.

All you need to send them is a sessionid. Make sure you associate sessionsIds with your orders in the db and check for the session cookie when the user request's your webpage.