How to call and recieve data using HTTPService?

I have a Firebase Database setup up. I have made a website with functions to send and receive data, for example in https://example.yolo their is a function called getData(), and in that function is return "yolo"; How would I get the roblox game to call the function (I already have it return data from the database in the website) than do print(variable) to print "yolo"? Because I have researched into using HTTPService, but none of them just call a javascript function, than get the data returned to print out what it got back.