Why doens't this work in ROBLOX?

[Frs4ken]

Trying to use this script (not mine) to autoclick in ROBLOX.
Didn't work in roblox so i tried it in firefox and it worked so why doesn't it work in ROBLOX?

#SingleInstance, Force
#NoEnv
SendMode Input
fire := 0

NumpadDiv::SetTimer, AutoFire, % (fire := !fire) ? "500" : "Off"

AutoFire:
ControlClick, x778 y390, ahk_class WINDOWSCLIENT,,,, Pos
return