This lesson discusses about the very basic concepts of OOJS
> Polymorphism – The ability for two classes to respond to the same (collection of) methods.
> Inheritance – The ability to define the behavior of one object in terms of another by sub-classing.
So, for example, we can create a new object and add several ad-hoc properties to it with the following code:
obj = new Object;
obj.x = 1;
obj.y = 2;