Question

I’d like to setup an introductory message to show to all new users. It should somehow store their info (cookie? IP address?) so that they (ideally) never see the message a second time. I know it’s possible with cookies, but what is the most reliable way to do this?

Thanks!

Answer 1

To do this reliably you would need to use Server Side Scripting. Javascript can be disabled and as such would not prove reliable anymore.

PHP would be simple – you can read the users IP address and User Agent (UA) with

<?php
    $IP = $_SERVER['REMOTE_ADDR'];
    $UA = $_SERVER['HTTP_USER_AGENT'];
?>

Store that information into a database and you can track the user. Combine that with a cookie (however again, this could be deleted by the user) and you have a pretty good tracking solution.

<?php
   // Set a cookie
   $userID = 'something';
   setcookie('UID', $userID);

   // Read a cookie
   echo($_COOKIE['uid']);
?>

Have a look on http://php.net/manual/en/function.setcookie.php for info on cookies.