How to set a cookie, remove a cookie and get the value of a cookie in PHP
PHP cookie management is a good example of how incredibly badly designed PHP is:
Set a cookie that expires when browser is closed
Note that you most probably want to set the path, which we do here:
$value = 0;
$expires = 0;
setcookie('cookie_name', $value, $expires, '/');
Remove cookie
setcookie ('cookie_name', FALSE, time()-10000);
Get cookie value
$_COOKIE['cookie_name']