What is the difference between null and undefined in JavaScript?

Question

I want to know what the difference is between null and undefined in JavaScript.

Answer 1

null - It is an assignment value, which is used with variable to represent no value (it's an object).

undefined - It is a variable which does not have any value assigned to it, so JavaScript will assign an undefined to it (it's a data type).

undeclared - If a variable is not created at all, it is known as undeclared.