PHP Sessions

A session is a way to store information (in variables) to be used across multiple pages.

What is a PHP Session?

When you work with an application, you open it, do some changes, and then you close it. This is much like a Session. The computer knows who you are. It knows when you start the application and when you end. But on the internet there is one problem: the web server does not know who you are or what you do, because the HTTP address doesn't maintain state.

Session variables solve this problem by storing user information to be used across multiple pages (e.g. username, favorite color, etc). By default, session variables last until the user closes the browser.

So; Session variables hold information about one single user, and are available to all pages in one application.


Start a PHP Session

A session is started with the session_start() function.


Session variables are set with the PHP global variable: $_SESSION.


In following Example we start a new PHP session and set some session variables:


Example

<?php
// Start the session
session_start();
?>
<!DOCTYPE html>
<html>
<body>

<?php
// Set session variables
$_SESSION["favcolor"] = "green";
$_SESSION["favanimal"] = "cat";
echo "Session variables are set.";
?>

</body>
</html>

Run Example>>



Note:
  • The session_start() function must be the very first thing in your document. Before any HTML tags.

    • Destroy a PHP Session

    To remove all global session variables and destroy the session, use session_unset() and session_destroy():


    To Unset single session variable use,unset($_SESSION["favcolor"])


    Example

    <?php
    session_start();
    ?>
    <!DOCTYPE html>
    <html>
    <body>

    <?php
    // remove all session variables
    session_unset();

    // destroy the session
    session_destroy();
    ?>

    </body>
    </html>

    Run Example>>



    Find How many Pepople Visite your Webpage

    By Following example you can find How many Pepople Visite your Webpage

    Example

    <?php
     if(!isset($_SESSION['view'])) echo $_SESSION['view']=null;
    $_SESSION['view']=1;
    if(isset($_SESSION['view']))
    {
    session_start();
    $_SESSION['view']++;
    echo "Your WebPage is ".$_SESSION['view']." times viewed by People";
    }
    ?>

    Run Example>>