JavaScript Function Invocation

The function invocation is used to execute the code inside the curly braces in the function definition by adding () after function name after it has been defined to invoke that particular function.

Following is the code for implementing JavaScript function invocation −


 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;
   .sample {
      font-size: 18px;
      font-weight: 500;
<h1>JavaScript Function Invocation</h1>
<div class="sample"></div>
<button class="Btn">CLICK HERE</button>
Click on the above buttons to invoke the function
   let sampleEle = document.querySelector(".sample");
   function helloWorld() {
      alert("HELLO WORLD");
   document.querySelector(".Btn").addEventListener("click", () => {


On clicking the “CLICK HERE” button −