You have a little parse error in your code:
$_COOKIE['userid]; will give a parse error, it should be:
$_COOKIE['userid'];

Just FYI that you typo'd :)


Actually, to be entirely precise, it checks whether the variable $debug evaluates to TRUE.

There is a vital difference between a variable that is set and a variable that evaluates to true.

This is important to note, because for starting programmers it's important to know the difference :)

For instance, if I SET my variable like this:
$debug = 0;

the variable is set fine, and it does exist fine. But it won't evaluate to TRUE, and so that if () will not occur.


If at any point you want to know if a variable is SET, use:

if you want to know if the variable evaluates to TRUE, use:

etc....

(for detailed hacking guidelines, wait a while until vB3 RC1 is out and we have the Hacking Document ready at vB.org :))