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raju
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Asked: 2020-09-05T20:31:46+00:00 In:

What is the difference between null and undefined in JavaScript?

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What is the difference between null and undefined in JavaScript?

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    3 Answers

    1. This answer was edited.

      Null and Undefined are both data types in JavaScript. Undefined is a variable that has been declared but not assigned a value. Null as an assignment value. … However, when you assign null to a variable, you are declaring that this value is explicitly empty.

      Example:

      <html>
   <body>
      <input type="text" id="Stackorigin">
      <script>
         var a = null; //NUll
         console.log( a );   //output: null
         console.log( typeof(a) );   //output: object
         var a;                      //undefined
         console.log(a); //undefined
         console.log(typeof(a))
      </script>
    </body>
</html>

       

       

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    2. The value ‘undefined’ denotes that a variable has been declared, but hasn’t been assigned any value. On the other hand, Javascript null refers to a non-existent object, which basically means ’empty’ or ‘nothing’. They’re both values usually used to indicate the absence of something . Also, undefined and null are two distinct types: undefined is a type itself (undefined) while null is an object .

       

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