A web page that uses Session Cookies stores a unique number in a small file on your computer.
This number is generated randomly by the web server (the computer on the Internet that is sending you this page).
This number is not based on any information about you or your computer. It is equivalent to the ticket number that you might be allocated in a shop queue, purely allocated at the moment you arrive at the web page.
The purpose of the number is to allow the web server to:
1) tell whether or not you have viewed a cartoon during the current
browsing session (not at some earlier time);
2) send you a different cartoon on request, if you have viewed a cartoon during the current session;
3) separate out requests for cartoons if there is more than one user accessing the page.
For example if user number one requests another cartoon by clicking on 'NEXT', by reading the unique Session Cookie the web server can identify what is the current cartoon and can compute which one to deliver. Similarly if a request for 'NEXT' is received from a second user the web server can recognise that this is indeed a request from another user, not the first, and compute and deliver the appropriate cartoon.
When each user closes the web page on this server the session data is automatically deleted as in no longer serves any purpose.
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