Scripts

Hello! I would like to create a script that tracks the number of creatures killed. Let's say I define "enemieskilledcounter = 0" in the map script. Will this variable be updated if I increment it in the combat script? I read the introduction to Lua, and it says that if you don't specify "local" for a variable, it will be accessible to all functions. But I'm not sure if this applies to a separate script or not. Or should I use SetGameVar to update the counter in the map script from the combat script?