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What is null in JavaScript | Basics

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JavaScript null represents the intentional absence of any object value. Simple null means the absence of a value. You can assign null to a variable to denote that currently, that variable does not have any value but it will have later on.

If you wish to shred a variable of its assigned value, you can simply assign ‘null’ to it.

var myVar = null;

Example null in JavaScript

Simple example code.

<!DOCTYPE html>
<html>
<body>

  <script>

   const a = null;
   console.log(typeof a);

   console.log(a);
 </script>

</body>
</html> 

Output:

What is null in JavaScript

Difference between null and undefined

When checking for null or undefined, beware of the differences between equality (==) and identity (===) operators, as the former performs type-conversion.

typeof null          // "object" (not "null" for legacy reasons)
typeof undefined     // "undefined"
null === undefined   // false
null  == undefined   // true
null === null        // true
null  == null        // true
!null                // true
isNaN(1 + null)      // false
isNaN(1 + undefined) // true

Do comment if you have any doubts or suggestions on this JS null topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version

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