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A session is a way to store information to be used across multiple pages. Session variables store user information which can be used across multiple pages. Session variables last until the user closes the browser.
In PHP, a session can be started with the session_start() function. Session variables are set with the $_SESSION variable. Let's assume we have one webpage called example1.php. On this page, we will start a new PHP session and set session variables.
example1.php
<?php
// Start the session
session_start();
?>
<!DOCTYPE html>
<html>
<body>
<?php
// Set session variables
$_SESSION["uname"] = "shayan";
$_SESSION["upass"] = "hunter";
echo "Session variables are set.";
?>
</body>
</html>
Now we will create a new page named example2.php. From this page, we will access the session variables we have set on the first page (example1.php).
example2.php
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<body>
<?php
// Echo session variables that were set on previous page
echo "Favorite color is " . $_SESSION["uname"] . ".<br>";
echo "Favorite animal is " . $_SESSION["upass"] . ".";
?>
</body>
</html>
We can also see all the session variables by using print_r($_SESSION).
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<body>
<?php
print_r($_SESSION);
?>
</body>
</html>
To modify a session variable, we just need to overwrite it.
Example:
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<body>
<?php
// to change a session variable, just overwrite it
$_SESSION["uname"] = "aakash";
print_r($_SESSION);
?>
</body>
</html>
To delete all the session variables and destroy the session, we can use session_unset() and session_destroy().
Example:
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<body>
<?php
// remove all session variables
session_unset();
// destroy the session
session_destroy();
?>
</body>
</html>
