A basic script that turns on a particleEmitter when a key is pressed isn't working? :/

Why is this not working I got the script to recognize what a plr was then after got the player's mouse to connect with a key getting pressed I don't know whats wrong because there are no output errors. Its so basic its annoying.

game.Workspace.ChildAdded:connect(function(plr)
mouse = plr:GetMouse()
mouse.KeyDown:connect(function(key)
if key == "f" then
        script.Parent.Enabled = true
    end
end)