How to Check Who Click a Button?

My current code does everything it needs to, but I need a bit of additional coding to check who was the player to click the TextButton. I don't know how to do that. Calling the fuction, and adding .Parent isn't working, as it would with, let's say, a Touched script.

Anything dealing with GUIs should be handled locally, so a script running on the client should be detecting all of the events and then requesting for a server-sided script to do something if necessary.