Grabbing variables from URL Query String within functions

Grabbing variables from URL Query String within functions

Is this possible?  I have a custom action button set to appear on each row of a view, and as part of the action I want to be able to take some values from the record in question, as well as a parameter from the URL query string.  I know this can be done in HTML views with parameters but is there any way to do this with a standard function script?