JavaScript | hasOwnProperty() Method

22 Nov, 2021
The hasOwnProperty() method in JavaScript is used to check whether the object has the specified property as its own property. This is useful for checking if the object has inherited the property rather than being it’s own.Syntax:  
object.hasOwnProperty( prop )
Parameters: This method accepts single parameter prop which holds the name in the form of a String or a Symbol of the property to test.Return Value: It returns a boolean value indicating whether the object has the given property as its own property. Example 1: This example checks the properties on an object. 
html
<!DOCTYPE html><html> <head>    <title>        JavaScript | hasOwnProperty() Method    </title></head> <body>    <h1 style="color: green">        GeeksforGeeks    </h1>     <b>        hasOwnProperty() method in JavaScript    </b>           <p>        Click on the button to check if the        properties are of the object.    </p>             <p>Output for own property:        <span class="outputProperty"></span>    </p>             <p>Output for not own property:        <span class="outputNonProperty"></span>    </p>       <button onclick="checkProperty()">        Check properties    </button>         <script type="text/javascript">         function checkProperty() {            let exampleObj = {};            exampleObj.height = 100;            exampleObj.width = 100;             // Checking for existing property            result1 = exampleObj.hasOwnProperty("height");             // Checking for non-existing property            result2 = exampleObj.hasOwnProperty("breadth");             document.querySelector(".outputProperty").textContent                        = result1;                         document.querySelector(".outputNonProperty").textContent                        = result2;        }    </script></body> </html>
Output:  
Before clicking the button:  
After clicking the button:  
Example 2: This example checks the properties on an object of a class. 
html
<!DOCTYPE html><html> <head>    <title>        JavaScript hasOwnProperty() method    </title></head> <body>    <h1 style="color: green">        GeeksforGeeks    </h1>         <b>        hasOwnProperty() method in JavaScript    </b>           <p>        Click on the button to check if the        properties are of the object.    </p>             <p>Output for own property:        <span class="outputProperty"></span>    </p>             <p>Output for not own property:        <span class="outputNonProperty"></span>    </p>       <button onclick="checkProperty()">        Check properties    </button>         <script type="text/javascript">         function checkProperty() {                         function Car(a, b) {                this.model = a;                this.name = b;            }             let car1 = new Car("Mazda", "Laputa");             // Checking for existing property            result1 = car1.hasOwnProperty("model");             // Checking for non-existing property            result2 = car1.hasOwnProperty("wheels");             document.querySelector(".outputProperty").textContent                        = result1;                         document.querySelector(".outputNonProperty").textContent                        = result2;        }    </script></body> </html>
Output:  
Before clicking the button:  
After clicking the button:  
Supported Browsers: The browsers supported by JavaScript hasOwnProperty() method are listed below: 
Google Chrome 1 and above
Firefox 1 and above
Internet Explorer 5.5 and above
Edge 12 and above
Safari 3 and above
Opera 5 and above
 
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