variable types

I don’t know if variable types is the right term, but I need an explanation of a few things that I just cannot find by myself. Just what is the difference between a normal (public) variable in JavaScript, and global and static variables? Some things I’ve read suggest that they can be used to resolve a dilemma I have in a script I’m writing, but I don’t understand what they are, how to use them, and what they do differently.

Normal variables are part of objects, static and global variables are part of module/ class. For example, if you create 10 cars on scene, each one should have it’s own speed (variable). But if you want to create car counter, you can add static variable to car script and increment it in Awake() - this variable will be shared between all cars

Another question; does the static variable only apply to the scene it’s in, or can you use it across multiple scenes?

Static variable is unique in whole program - so you can use it across scenes