Understanding lazy loading in JavaScript

The guide explores the concept of lazy loading in JavaScript, highlighting its significance in optimizing web performance by delaying the loading of non-essential resources until they are needed. It explains how the native lazy loading API and the Intersection Observer API can be utilized to implement this technique effectively, improving page load times, reducing bandwidth usage, and enhancing user experience, particularly in scenarios involving large images, videos, or infinite scroll features. The guide also provides insights into best practices for lazy loading, such as determining which elements to defer, setting up the Intersection Observer, and providing fallback content to maintain usability for users with JavaScript disabled. Moreover, it discusses when lazy loading should be applied or avoided, emphasizing its benefits in improving web accessibility and user retention, while cautioning against its use for critical resources necessary for initial page rendering or essential for SEO purposes.