How to add, access JavaScript object methods?

Javascript Web Development Object Oriented Programming

Following is the code to add, access JavaScript object methods −

Example

<!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;
   }
</style>
</head>
<body>
<h1>Add, Access JavaScript object methods</h1>
<div style="color: green;" class="result"></div>
<button class="Btn">CHECK</button>
<h3>Click on the above button to add and access object methods.</h3>
<script>
   let resEle = document.querySelector(".result");
   let obj = {
      firstName:'Rohan',
      lastName: 'Sharma',
      Age:'22',
   }
   document.querySelector(".Btn").addEventListener("click", () => {
      obj.welcome = function(){return 'Welcome '+this.firstName+' '+this.lastName};
      resEle.innerHTML = 'Adding function welcome : ' + obj.welcome + '';
      resEle.innerHTML += 'Accessing function welcome : ' + obj.welcome() + '';
   });
</script>
</body>
</html>