JavaScript Instanceof Operator
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:
let gfg = objectName instanceof objectType
Parameters:
- objectName: States the name of the Object.
Return Value: This method 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.
Example 1: Below is the example of the Instanceof Operator.
html
<!DOCTYPE html><html lang="en"><head> <title> How to Check/Uncheck the checkbox using JavaScript ? </title></head><body> <h1 style="color:green"> GeeksforGeeks </h1> <h3> Instanceof Operator. </h3> <p id="GFG"></p> <script> let a = ["Geeks", "for", "Geeks"]; document.getElementById("GFG").innerHTML = (a instanceof Array) + "<br>" + (a instanceof Number); </script></body></html> |
Output:
JavaScript Instanceof Operator
Example 2: Below is the example of the Instanceof Operator.
html
<!DOCTYPE html><html lang="en"><head> <title> How to Check/Uncheck the checkbox using JavaScript ? </title></head><body> <h1 style="color:green"> GeeksforGeeks </h1> <h3> Instanceof Operator. </h3> <p id="GFG"></p> <script> let fruits = ["Apple", "Mango", "Banana"]; document.getElementById("GFG").innerHTML = (fruits instanceof Array) + "<br>" + (fruits instanceof Object) + "<br>" + (fruits instanceof String) + "<br>" + (fruits instanceof Number); </script></body></html> |
Output:
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JavaScript Instanceof Operator
Example 3: Demonstrating that String and Date objects are also a type of Object (derived from Object).
Javascript
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); |
Output:
true
false
true
true
true
false
We have a complete list of Javascript Operators, to check those please go through the Javascript Operators Complete Reference article.
Supported Browsers:
- Google Chrome
- Firefox
- Edge
- Opera
- Apple Safari
