Why cookies dont expire after closing browser?

Question

In books and tutorials related with Web-programming written that cookies expire when user close browser. So I cant understand why after closing browser(Opera) I can see the

Answer 1

Cookies are of two different types:

• session cookies, held in memory, and which expire once the browser exits
• persistent cookies, which have a time-to-live, are persisted on disk, and are sent by the browser until their time-to-live has elapsed.

Read http://en.wikipedia.org/wiki/HTTP_cookie