JAVASCRIPT

What is the Difference between Undefined, undeclared, Null

What is the Difference between Undefined, undeclared, Null

// undefined means that the variable has not been declared, or has not been given a value.
// Undefined is used for unintentionally missing values.
var dog;
console.log(dog);


// Undeclared means the variable does not exist in the program at all.
console.log(cat);


// Null used for intentionally missing values. It contains no value.

difference between undefined and null?

null is a special object because typeof null returns 'object'. 
On the other hand,
undefined means that the variable has not been declared,
or has not been given a value.

what is the difference between null and undefined

Undefined  used for unintentionally missing values.

Null       used for intentionally missing values. 

difference between undefined and null

null == undefined