A session is a way to store information (in variables) to be used across multiple pages. Unlike a cookie, the information is not stored on the users computer.
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 doesnt 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 variables are set with the PHP global variable: $_SESSION.
Now, lets create a new page called "demo_session1.php". In this page, we start a new PHP session and set some session variables:
Get PHP Session Variable Values
Next, we create another page called "demo_session2.php". From this page, we will access the session information we set on the first page ("demo_session1.php").
Notice that session variables are not passed individually to each new page, instead they are retrieved from the session we open at the beginning of each page (
Also notice that all session variable values are stored in the global $_SESSION variable:
Another way to show all the session variable values for a user session is to run the following code:
Modify a PHP Session Variable
To change a session variable, just overwrite it:
Destroy a PHP Session
To remove all global session variables and destroy the session, use