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Basic PHP Sessions

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Starting a Session
A session is a way to store information (in the form of variables) to be used across multiple pages. Unlike a cookie, specific variable information is not stored on the users computer. It is also unlike other variables in the sense that we are not passing them individually to each new page, but instead retrieving them from the session we open at beginning of each page.

Call this code mypage.php

 <?php 
 // this starts the session 
 session_start(); 
 
 // this sets variables in the session 
 $_SESSION['color']='red'; 
 $_SESSION['size']='small'; 
 $_SESSION['shape']='round'; 
 print "Done";
 ?> 
The first thing we do with this code, is open the session using session_start(). We then set our first session variables (color, size and shape) to be red, small and round respectively.

Just like with our cookies, the session_start() code must be in the header and you can not send anything to the browser before it. It's best to just put it directly after the <?php to avoid potential problems.

So how will it know it's me? Most sessions set a cookie on your computer to uses as a key... it will look something like this: 350401be75bbb0fafd3d912a1a1d5e54. Then when a session is opened on another page, it scans your computer for a key. If there is a match, it accesses that session, if not it starts a new session for you.

Related Video
Basic PHP Syntax
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