What happens if I don't pass a parameter in a Javascript function?

Question

I am new to the world of Javascript and am tinkering with writing very basic functions and stumbled upon the example below by accident and am unsure why it works when I am n

Answer 1

Because there's no error until the function expects to be able to work with the parameter that you're supposed to pass.

For example:

function myfunction(x) {
    return x*2;
}

Would throw an error; albeit probably only a NaN (in this case) or a variable is undefined.