Case Studies in Lazy Loading Media

Introduction

Lazy loading is a design pattern that postpones loading non-essential resources at the point of page load. This lesson explores case studies that illustrate the effectiveness of lazy loading for media delivery, particularly images and videos.

What is Lazy Loading?

Lazy loading is a technique that defers the loading of images or other media until they are needed, which improves performance, reduces bandwidth, and enhances the overall user experience.

Key Benefits:

• Improved page load speed
• Reduced initial loading time
• Lower resource consumption
• Better SEO rankings due to faster loading pages

Case Study 1: E-commerce Site

<img src="placeholder.jpg" data-src="product-image.jpg" class="lazy">
            

document.addEventListener("DOMContentLoaded", function() {
    const lazyImages = document.querySelectorAll("img.lazy");

    const observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                const img = entry.target;
                img.src = img.dataset.src;
                img.classList.remove("lazy");
                observer.unobserve(img);
            }
        });
    });

    lazyImages.forEach(image => {
        observer.observe(image);
    });
});
            

Case Study 2: News Platform

<video src="placeholder.mp4" data-src="news-video.mp4" class="lazy-video"></video>
            

document.addEventListener("DOMContentLoaded", function() {
    const lazyVideos = document.querySelectorAll("video.lazy-video");

    const observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                const video = entry.target;
                video.src = video.dataset.src;
                video.classList.remove("lazy-video");
                observer.unobserve(video);
            }
        });
    });

    lazyVideos.forEach(video => {
        observer.observe(video);
    });
});
            

Best Practices

• Use placeholders that are lightweight to improve perceived performance.
• Consider using the loading="lazy" attribute for images and iframes where supported.
• Implement fallback mechanisms for browsers that do not support lazy loading.
• Test across devices and browser versions to ensure consistent performance.

FAQ