Cookies are small text files stored on a user's device that are used to identify users and customize their experience. Session data is stored on the server to identify users across page requests during a browser session, using a session ID sent back and forth via cookies or URL rewriting. Common PHP functions for working with sessions include session_start(), session_register(), $_SESSION, and session_unset().

2.  Text file
kB
Browser

(Name) (Value)
(Expiry Date)
Host Path

3.  Cookies
Web Server
Client HTTP
Header
 Client HTTP Header
Cookies
Client
Cookies
Client

11. cookiefo
rm.jsp

13. setcookie
.jsp

14. setcookie
.jsp

17.  Session)
Web Server
Client
 Client) Session
Session ID Web Server

18. 
session_start()
 session_start()
Client session id
session id
session_id()

19. 
session_register()
session_register (

session_register("myname");
// myname

20. 
HTTP_SESSION_VARS
$HTTP_SESSION_VARS['

HTTP_SESSION_VARS['name']='s
ompot';
// name

21. 
SESSION
$_SESSION['

SESSION['name']='sompot';
// name

22. 
unset($_SESSION['
session_unregister(

session_unset();

25. LoginSes
sion.jsp

27. LoginSessi
on2.jsp