How to Resize a Navigation Bar on Scroll with CSS and JavaScript

1. Introduction

In today’s web development landscape, creating websites with smooth and engaging user experiences is crucial. One essential aspect of a website’s navigation is the navigation bar, which allows users to access various sections of the site effortlessly. In this article, we will explore how to resize a navigation bar on scroll using CSS and JavaScript, enhancing the user’s experience and providing an attractive design element.

2. Understanding the Navigation Bar

2.1 What is a Navigation Bar?

A navigation bar, often referred to as a navbar, is a user interface component that typically appears at the top of a website. It contains links to different pages or sections within the site, making it easier for users to navigate and find the desired content.

2.2 Importance of Resizing on Scroll

Resizing the navigation bar on scroll can make a significant impact on the website’s overall look and feel. By shrinking the navbar as the user scrolls down the page, you can create a more immersive experience and allow the content to take center stage. This effect is not only visually appealing but also helps in maximizing the available screen space.

3. The Basics of CSS and JavaScript

3.1 CSS Overview

Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation of a document written in HTML. With CSS, you can control the layout, colors, fonts, and other visual aspects of your web page.

3.2 JavaScript Overview

JavaScript is a high-level, interpreted programming language that enables interactive and dynamic website development. It allows you to add behavior to your web pages, making them more responsive and user-friendly.

4. Creating the HTML Structure

Before we dive into the CSS and JavaScript coding, let’s set up the HTML structure for our navigation bar. You can use a simple HTML unordered list (ul) to create the navigation links.

<!-- HTML Structure for the Navigation Bar -->
<nav id="navbar">
    <li><a href="#home">Home</a></li>
    <li><a href="#about">About</a></li>
    <li><a href="#services">Services</a></li>
    <li><a href="#contact">Contact</a></li>

5. Styling the Navigation Bar with CSS

5.1 Setting up the Default Navbar

Now, let’s begin by styling the default version of the navigation bar using CSS. We’ll add some basic styles to make it look visually appealing before implementing the scroll-resizing effect.

/* CSS for the Default Navigation Bar */
#navbar {
  background-color: #333;
  padding: 10px;
  transition: background-color 0.3s ease;

#navbar ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  display: flex;

#navbar li {
  margin-right: 20px;

#navbar a {
  color: white;
  text-decoration: none;
  font-size: 18px;

5.2 Writing CSS for Resizing on Scroll

To achieve the resizing effect, we’ll use JavaScript to add and remove a CSS class to the navigation bar based on the scroll position. When the user scrolls down, the “small” class will be added, reducing the navbar’s size.

/* CSS for the Resizing Navigation Bar */
#navbar.small {
  padding: 5px;

#navbar.small ul {
  margin-top: 5px;

#navbar.small a {
  font-size: 16px;

6. Implementing the JavaScript Functionality

6.1 The JavaScript Code Explained

Now, let’s write the JavaScript code to achieve the desired resizing effect. We’ll use the window.onscroll event to trigger the function that adds or removes the “small” class based on the scroll position.

// JavaScript for Resizing on Scroll
window.onscroll = function () {
  var navbar = document.getElementById("navbar");
  if (window.pageYOffset > 50) {
  } else {

6.2 Adding the JavaScript to the HTML File

To make the JavaScript code work, we need to include it in our HTML file within a script tag.

<!-- Adding the JavaScript to the HTML File -->
  // JavaScript code here

7. Testing and Troubleshooting

Before deploying the code to the live website, it’s essential to thoroughly test the navigation bar resizing on different browsers and devices. This step helps identify any potential issues and ensures a smooth user experience.

8. Additional Customization Options

8.1 Changing Background Colors

You can customize the background colors of the navigation bar to match your website’s theme. Experiment with different color combinations to achieve the desired look and feel.

8.2 Adding Smooth Transitions

To make the resizing effect more visually appealing, consider adding CSS transitions. This smooth animation provides a seamless experience when the navigation bar shrinks or expands.

8.3 Customizing the Scroll Threshold

You can adjust the scroll threshold value (currently set at 50 pixels in our example) to control when the resizing effect triggers. Finding the right threshold ensures that the navigation bar resizes at the most appropriate time during scrolling.

9. Optimizing for Different Devices

It’s crucial to ensure that the resizing effect works well on various devices, including desktops, tablets, and mobile phones. Test the functionality on different screen sizes and make necessary adjustments to enhance responsiveness.

10. Conclusion

Resizing a navigation bar on scroll can greatly improve the user experience of your website. By utilizing CSS and JavaScript, you can create an engaging and visually appealing design element that enhances navigation and content visibility. Experiment with different customization options to match your website’s theme and keep the user experience at the forefront.


Can I apply the resizing effect to multiple navigation bars on the same page?

Absolutely! You can use the same JavaScript logic and assign different IDs to each navigation bar to resize them independently.

Does this resizing effect work on all web browsers?

Yes, the JavaScript and CSS used in this article are compatible with major modern web browsers.

Can I combine this resizing effect with other CSS animations?

Yes, you can combine this resizing effect with other CSS animations to create more dynamic and interactive navigation bars.

Is it possible to use this technique on a single-page website with anchor links?

Yes, this technique can be applied to a single-page website with anchor links. The resizing effect will work as the user scrolls through the different sections.

Are there any performance considerations with using JavaScript for resizing?

While the JavaScript used here is lightweight and shouldn’t cause performance issues, it’s always a good practice to test the website’s performance and make optimizations if necessary.

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