Why dose this script not work?

Here is the script...

function onKeyDown(Key) if Key=="k" then Game.Player.Humanoid.Health = 0 end end

Can some one fix this script please? And maybe tell my why it's didn't work?

Seriously, do you know what functions are? This functions means nothing because is NOT called. For this script works you need to connect on the key event typed, use this at the end of your code:

local thePlayer = game.Players.LocalPlayer
local theInputs = thePlayer:GetMouse()
theInputs.KeyDown:connect(onKeyDown)

I think you need to learn functions...