Ok if i have this:

if (isset($old)):

and is shows a page of Old stuff.

and the url looks like this

/stuff/things.php?old=

i want the URL that looks like this

/stuff/things.php?old=edit

or

/stuff/things.php?old=new

what php code do i need? do i do

if (isset($old=edit)):

or

if (isset($old=new)):


i'm so lost and i can't find any help in my PHP book.. manily cause it's at work, and i'm not.