Global Interference

I have a form posting values from its text fields to a switch constructor. it posts to $_SERVER['PHP_SELF']."?action=Test In the switch 'Test' I want to echo the variable I have posted. I assumed I would print them out such as this- echo $GLOBALS['Font']; // Font being the name of the variable However I get the undefined index error message. I echo'ed my globals to see if it was there and there is a list of the values posted in my form, so I assume that it is now a global variable and it has a value- so why do I get this message and why can I not access the variable? thanks once again