PHP setcookie for both localhost and domain

something it wasn't clear to me for a while was that domain names must contain at least two dots (.), hence 'localhost' is invalid and the browser will refuse to set the cookie! instead for localhost you should use false.

to make your code work on both localhost and a proper domain, you can do this:

<?php $domain = ($_SERVER['HTTP_HOST'] != 'localhost') ? $_SERVER['HTTP_HOST'] : false; setcookie('cookiename', 'data', time()+60*60*24*365, '/', $domain, false); ?>