How does gmail keep a user logged in?

I wonder how gmail/Google keeps a user logged in even across sessions. And how (e.g. cookies) and what (e.g. time) do t开发者_如何学Chey use to decide to re-prompt the user for the login?

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The short answer is that cookies do not have to expire when you close down the broweser or the machine they are on. Depending on constraints configured in the browser, if the server sets an expiry date in the future, the browser will continue to present the cookie until that expiry time.

C.

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Well cookies are stored in your local machine, you can see those in totals -content settings -cookies.You can clear the cookies as well.So your information is stored there.More over about the sessions if they have been implemented on the websites...They could be destroyed by two methods ,one is by giving the time for session to expire the another way is when you forcefully want to expire the session then session abandon method is used.You must have seen sometimes if you don't scroll through a page for some time, then its written there your session has been expired. Sessions are executed on the server side and there values can be stored on the client side in the cookies as well. Hope it would help you to understand William