Session support in PHP consists of a way to preserve certain data across subsequent accesses. Session is a essential concept for modern web appliactions.
Session support consists of a way to preserve certain data across subsequent accesses. A visitor accessing your web site is assigned a unique id, the so-called session id. This is either stored in a cookie on the user side or is propagated in the URL. The session support allows you to register arbitrary numbers of variables to be preserved across requests.
When a visitor accesses your site, PHP will check whether a specific session id has been sent with the request. If this is the case, the prior saved environment is recreated.
Page 1:
<?php // session_start() must be called before outputing anything to the browser session_start(); $_SESSION["counter"]++; ?> <html> ... </html>
Page 2:
<?php // session_start() must be called before outputing anything to the browser session_start(); ?> <html> <body> <p> <?php echo "counter: " . $_SESSION["counter"]; ?> </p> </body> </html>