ShadowHandler - LocalScript!

local Lighting = game:GetService("Lighting") -- Defining The Lighting Service!

local Button = script.Parent.ShadowButton -- Getting The Button From The GUI

local On = true -- Setting A Variable To Keep Track Of The State Of The Shadows

Button.MouseButton1Click:Connect(function() -- Connecting If It Is Clicked
    if On == false then -- Checking If On Is False / Shadows Is Off
        Lighting.GlobalShadows = true
        Button.Text = "Shadows : ON" -- Setting The Text On The GUI To Show The Shadows Are On
        On = true -- Setting The Variable To True To Keep Track Of The State
    else -- Otherwise
        Lighting.GlobalShadows = false
        Button.Text = "Shadows : OFF" -- Setting The Text On The GUI To Show The Shadows Are Off
        On = false -- Setting The Variable To False To Keep Track Of The State
    end
end) -- Ending The Function