Function context (“this”) in nested functions

Question

When you invoke a top-level function in Javascript, the this keyword inside the function refers to the default object (window if in a browser). My understanding is that

Answer 1

It does not depend where the function is declared but how it is called:

var obj = {
   f: function() {
       return this;
   }
}

var f = obj.f;

console.log(obj.f()) // obj
console.log(f()) // window/default obj

Or in other words. The syntax obj.f() executes the function with this=obj while f() executes the function with this=window. In JavaScript the caller specifies the value of this.