JavaScript Instanceof Operator

Below is the example of the Instanceof Operator.

  • Example:
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    <!DOCTYPE html> 
    <html> 
      
    <body> 
        <center> 
            <h1 style="color:green">GeeksforGeeks</h1> 
      
            <p id="GFG"></p> 
      
            <script> 
                var a = ["Geeks", "for", "Geeks"]; 
      
                document.getElementById("GFG").innerHTML = 
                    (a instanceof Array) + "<br>" + 
                    (a instanceof Number); 
            </script> 
        </center> 
    </body> 
      
    </html> 

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  • Output:
    

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The instanceof operator in JavaScript is used to check the type of an object at run time. It returns a boolean value if true then it indicates that the object is an instance of a particular class and if false then it is not.


Syntax:


var gfg = objectName instanceof objectType


Parameters:

objectName: States the name of Object.


Example-1: objectTypes.













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<!DOCTYPE html> 


<html> 


  


<body> 


    <center> 


        <h1 style="color:green">GeeksforGeeks</h1> 


  


        <p id="GFG"></p> 


  


        <script> 


            var fruits = ["Apple", "Mango", "Banana"]; 


  


            document.getElementById("GFG").innerHTML = 


                (fruits instanceof Array) + "<br>" + 


                (fruits instanceof Object) + "<br>" + 


                (fruits instanceof String) + "<br>" + 


                (fruits instanceof Number); 


        </script> 


    </center> 


</body> 


  


</html> 



















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Output:




Example-2: Demonstrating that String and Date objects are also a type of Object (derived from Object).











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<!DOCTYPE html> 


<html> 


  


<body> 


    <h1 style="color:green">GeeksforGeeks</h1> 


  


    <p id="GFG"></p> 


  


    <script> 


        var myString = new String(); 


        var myDate = new Date(); 


  


        console.log(myString instanceof Object); 


        console.log(myString instanceof Date); 


        console.log(myString instanceof String); 


        console.log(myDate instanceof Date); 


        console.log(myDate instanceof Object); 


        console.log(myDate instanceof String); 


    </script> 


</body> 


  


</html> 



















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Output




Supported Browsers:


    

  • Google Chrome
    • 

  • Firefox
    • 

  • Edge
    • 

  • Opera
    • 

  • Apple Safari
    • 



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