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

OK, we may get confused when we hear about null and undefined, but let's start it simple, they both are falsy and similar in many ways, but weird part of JavaScript, make them a couple of significant differences, for example, typeof null is 'object' while typeof undefined is 'undefined'.

typeof null; //"object"
typeof undefined; //"undefined";

But if you check them with == as below, you see they are both falsy:

null==undefined; //true

Also you can assign null to an object property or to a primitive, while undefined can simply be achieved by not assigning to anything.

I create a quick image to show the differences for you at a glance.