how to lazy load images in html

Lazy loading is a technique used to improve website user experience by delaying the loading of images until they are needed. This means that images won't load until users scroll to the part of the page where they appear. This can significantly improve page load time, especially on web pages with multiple images. In this article, we will explain how to lazy load images in HTML.

Why lazy load images?

Lazy loading images can reduce page load time and improve website performance. When a website has multiple images, it can take a long time to load, especially on slower internet connections. This can lead to a poor user experience and a high bounce rate. By lazy loading images, you can reduce the amount of data that is downloaded, which can significantly improve website speed and performance.

How to lazy load images in HTML

To lazy load images in HTML, you will need to use JavaScript. There are several ways to implement lazy loading, but in this article, we will focus on using the Intersection Observer API. The Intersection Observer API allows you to track when an element enters or exits the viewport. This can be used to load images only when they are visible to users.1. First, add a placeholder image to your HTML code. This will be replaced with the actual image when it is loaded. You can use a low-quality image or a small-sized image as a placeholder.

2. Next, add the Intersection Observer API to your JavaScript code. You can use the following code:```const lazyLoad = (target) => { const io = new IntersectionObserver((entries, observer) => { entries.forEach((entry) => { if (entry.isIntersecting) { const img = entry.target; const src = img.getAttribute(\"data-src\"); img.setAttribute(\"src\", src); img.classList.remove(\"lazy-load\"); observer.disconnect(); } }); }); io.observe(target);};const images = document.querySelectorAll(\".lazy-load\");images.forEach(lazyLoad);```3. Finally, add the CSS for the placeholder image. You can use the following CSS:```.lazy-load { opacity: 0; transition: opacity 0.3s ease-in-out;}.lazy-load.loaded { opacity: 1;}```This will make the placeholder image transparent until the actual image is loaded. When the actual image is loaded, the placeholder image will become opaque.

Conclusion

Lazy loading images can significantly improve website performance and user experience. By delaying the loading of images until they are needed, you can reduce page load time and improve website speed. To lazy load images in HTML, you can use the Intersection Observer API along with JavaScript. This technique is easy to implement and can have a positive impact on your website's performance.