Using a button on a Universal Page to pass a global variable as a paramter?

I was wondering if its possible to say pass the global $username variable to a script from clicking a button on a Universal Page. In examples I have only found parameters to be static entries. Any help to a solution would be appreciated. If its not possible then let me know and I will have to create a Dashboard.
Cheers Carl.

Its ok I have found the answered my own question.

So the $uajob variable that’s present in the script when executed holds the value of the user that executed it so I wont need to pass it from the button on the page. All is good.