Passing parameters to callback functions JavaScript

Following is the code for passing parameters to callback functions in JavaScript −


 Live Demo

<!DOCTYPE html>
<html lang="en">
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
      font-size: 20px;
      font-weight: 500;
      color: blueviolet;
<h1>Passing parameters to callback functions</h1>
<div class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>Click on the above button to pass parameter to callback function add2 and call it</h3>
   let resEle = document.querySelector(".result");
   function add2(a) {
      return a + 2;
   function multiply9(fn, num) {
      return fn(num) * 9;
   document.querySelector(".Btn").addEventListener("click", () => {
      resEle.innerHTML = "The number returned = " + multiply9(add2, 8);


On clicking the ‘CLICK HERE’ button −