Remove a cookie

Question

When I want to remove a Cookie I try

unset($_COOKIE[\'hello\']);

I see in my cookie browser from firefox that the cookie still exists. How

Answer 1

To reliably delete a cookie it's not enough to set it to expire anytime in the past, as computed by your PHP server. This is because client computers can and often do have times which differ from that of your server.

The best practice is to overwrite the current cookie with a blank cookie which expires one second in the future after the epoch (1 January 1970 00:00:00 UTC), as so:

setcookie("hello", "", 1);