JavaScript - instanceof Operator
The JavaScript instanceof operator checks if an object is an instance of a specific class. It returns true if the object is an instance of a specific class, false otherwise.
Syntax
objectName instanceof objectType
Return Value
Returns true if the object is an instance of a specific class, false otherwise.
Example:
The example below shows the usage of instanceof operator.
var Num = [10, 20, 30]; var txt; //using instanceof operator txt = "Num instanceof Array : " + (Num instanceof Array) + "<br>"; txt = txt + "Num instanceof Object : " + (Num instanceof Object) + "<br>"; txt = txt + "Num instanceof Number : " + (Num instanceof Number) + "<br>"; txt = txt + "Num instanceof String : " + (Num instanceof String) + "<br>";
The output (value of txt) after running above script will be:
Num instanceof Array : true Num instanceof Object : true Num instanceof Number : false Num instanceof String : false
Example:
Lets consider one more example, where string and dates objects are used with instanceof operator.
var Str = new String(); var Dt = new Date(); var txt; //using instanceof operator txt = "Str instanceof Object : " + (Str instanceof Object) + "<br>"; txt = txt + "Str instanceof Number : " + (Str instanceof Number) + "<br>"; txt = txt + "Str instanceof String : " + (Str instanceof String) + "<br>"; txt = txt + "Dt instanceof Object : " + (Dt instanceof Object) + "<br>"; txt = txt + "Dt instanceof Date : " + (Dt instanceof Date) + "<br>"; txt = txt + "Dt instanceof String : " + (Dt instanceof String) + "<br>";
The output (value of txt) after running above script will be:
Str instanceof Object : true Str instanceof Number : false Str instanceof String : true Dt instanceof Object : true Dt instanceof Date : true Dt instanceof String : false
❮ JavaScript - Operators