How to add properties and methods to an existing object in JavaScript?


Following is the code for adding properties and methods to an existing object in JavaScript −

Example

 Live Demo

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
   }
   .result {
      font-size: 20px;
      font-weight: 500;
      color: blueviolet;
   }
</style>
</head>
<body>
<h1>Add properties and methods to an existing object in JavaScript</h1>
<div class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>Click on the above button to add property and methods to student object and display
them</h3>
<script>
   let resEle = document.querySelector(".result");
   let BtnEle = document.querySelector(".Btn");
   let student = {
      };
      BtnEle.addEventListener("click", () => {
         student.name = 'Rohan Sharma';
         student.age = 16;
         student.place = 'Delhi';
         student.displayInfo = function(){
         return 'Name = '+this.name+' : Age = '+this.age+' : Place = '+this.place;
      }
      resEle.innerHTML += student.displayInfo();
   });
</script>
</body>
</html>

Output

On clicking the ‘CLICK HERE’ button −

Updated on: 22-Jul-2020

158 Views

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