Leaderboard

Sorry but no, it is not what you thought. Seems a quick primer is in order. PHP handles exactly one page request at a time. When it finishes with a page, it completely forgets everything that happened. You can't set a variable on one page and get it in another page. Obviously that would be a huge limitation to making a website work, and that is why things like databases and cookies and sessions exist. That means there is no transfer of "control" between pages. PHP doesn't remember that the user was on trial-offer.php and is now going to checkout.php. All it knows is that someone is trying to request checkout.php, and they may or may not be sending data too. $_POST is not a database or cookie or session. It's a variable. A variable that you can reference from anywhere in your code, but just like every other variable, it's only usable for that one page. If you made any changes to it (which is a bad practice so don't do that) then you could see those changes for the rest of the page, but whatever you do will not be available on another page. Same for $_GET. $_GET gets its information from the query string - the stuff after the question mark in the URL. PHP looks at the query string, parses it, and shoves the data into $_GET for your convenience. $_POST gets its information from POSTed form data. The most common way to send POSTed form data is with a <form> whose method=POST. PHP looks at the data sent to the server, parses it, and shoves the data into $_POST for your convenience. If you have a form with an action="" then the browser will be nice and assume you meant action="(the current URL)". That's how form data goes back to your page: because the browser told your server that it wanted the same URL with some POSTed data. If you have a form with an action="checkout.php" then the browser doesn't have to assume anything, and it will tell the server that it wants checkout.php with some POSTed data.