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null is used to indicate that a variable does not have a value.




This example shows the difference between null and undefined.

var foo; // undefined, there is no value assigned
var bar = null; // null, states that there is no value


null is the only value of the Null type

null vs. undefined

null can be assigned to a variable to represent no value.

undefined means a value is declared but not initialized, it doesn’t have a value assigned to it.

Other than that, null is an object, while undefined is a type.