JavaScript Code Dynamic Background Images

Dynamic Background Changer project. This project will create a web page that cycles through captivating background images at a set interval. Here’s a step-by-step breakdown along with the full JavaScript code and description.

Project: Dynamic Background Changer

Step 1: HTML Structure

Create an HTML file named index.html and set up the basic structure.

<!DOCTYPE html>

<html lang=”en”>


    <meta charset=”UTF-8″>

    <meta name=”viewport” content=”width=device-width, initial-scale=1.0″>

    <title>Dynamic Background Changer</title>

    <link rel=”stylesheet” href=”styles.css”>



    <div class=”container”>

        <h1>Dynamic Background Changer</h1>


    <script src=”script.js”></script>



Step 2: CSS Styling

Create a CSS file named styles.css for basic styling.

body {

    font-family: Arial, sans-serif;

    background-color: #f0f0f0;

    margin: 0;

    padding: 0;

    display: flex;

    justify-content: center;

    align-items: center;

    height: 100vh;

    transition: background-image 1s ease-in-out;


.container {

    background-color: #fff;

    padding: 20px;

    border-radius: 5px;

    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);

    width: 300px;

    text-align: center;


h1 {

    font-size: 24px;

    margin-bottom: 10px;


Step 3: JavaScript Logic

Create a JavaScript file named script.js for the application logic.

const images = [





const body = document.body;

let currentIndex = 0;

function changeBackground() { = `url(‘images/${images[currentIndex]}’)`;

    currentIndex = (currentIndex + 1) % images.length;


setInterval(changeBackground, 5000);

Step 4: Images

Create a folder named images and place your background images (e.g., image1.jpg, image2.jpg, etc.) inside it.

Step 5: Testing

Open the index.html file in a web browser. You should see a web page with the title “Dynamic Background Changer.” The background image will change automatically every 5 seconds.

Congratulations! You’ve successfully created a Dynamic Background Changer using HTML, CSS, and JavaScript. This project demonstrates how you can use JavaScript to create dynamic and visually engaging web experiences by cycling through a series of background images.


In this project, we’ve created a web page that showcases a captivating Dynamic Background Changer. Here’s how it works:

  1. We’ve defined an array called images that holds the filenames of our background images.
  2. We access the body element using document.body.
  3. The changeBackground function changes the background image of the body. It sets the backgroundImage property with the path to the current image in the images array.
  4. We use the modulo operator (%) to cycle through the images in a loop. This ensures that when the index exceeds the number of images, it wraps around to the first image.
  5. Finally, we use setInterval to call the changeBackground function every 5000 milliseconds (5 seconds), causing the background image to change automatically.

By following these steps, the code creates a captivating Dynamic Background Changer that keeps your web page visually engaging and ever-changing.

Step 1: Define the Background Images

const images = [







Here, we’ve defined an array named images that holds the filenames of the background images. You can replace these filenames with your own images. This array acts as a repository of images to cycle through.

Step 2: Access the Body Element

const body = document.body;

In this step, we’re using document.body to get a reference to the <body> element of the HTML document. This will allow us to change the background of the entire page.

Step 3: Create a Counter Variable

let currentIndex = 0;

We initialize a currentIndex variable to keep track of the current image in the images array. This variable will help us cycle through the images.

Step 4: Define the changeBackground Function

function changeBackground() { = `url(‘images/${images[currentIndex]}’)`;

    currentIndex = (currentIndex + 1) % images.length;


Here’s a detailed breakdown of the changeBackground function:

  • When the changeBackground function is called, it does the following:
    • It sets the backgroundImage property of the <body> element using the property. The template literal ${images[currentIndex]} dynamically selects the current image based on the value of currentIndex.
    • It uses the modulo operator % to increment currentIndex and cycle through the images. When currentIndex reaches the length of the images array, it wraps around to 0, ensuring that the images loop.

Step 5: Set Up Automatic Background Changes

setInterval(changeBackground, 5000);

We use setInterval to repeatedly call the changeBackground function at a set interval of 5000 milliseconds (5 seconds). This interval will cause the background image to change automatically every 5 seconds.


In summary, the JavaScript code for the Dynamic Background Changer project:

  • Sets up an array of background image filenames.
  • Retrieves the <body> element.
  • Maintains a counter to track the current image.
  • Defines a function to change the background image and cycle through the images.
  • Uses setInterval to repeatedly call the function, resulting in automatic background changes.

By following these steps, the code creates a dynamic and visually engaging web experience where the background images cycle through at a set interval, providing an eye-catching effect on the web page.