What are the best practices for implementing lazy loading?

What are the best practices for implementing lazy loading in my web app?

Lazy loading is a technique to delay the loading of non-essential resources until they're needed. Here are some best practices: 1. Use the loading attribute in images and iframes. 2. Implement Intersection Observer API for better performance. 3. Prioritize above-the-fold content. 4. Test loading times to ensure a smooth user experience.

Can you explain how the Intersection Observer API works?

Sure! The Intersection Observer API allows you to asynchronously observe changes in the intersection of a target element with an ancestor element or the viewport. This means you can trigger loading of images or other resources only when they are about to enter the viewport, improving performance.

What are some common mistakes to avoid with lazy loading?

Common mistakes include: 1. Not lazy loading critical resources, which can lead to a poor user experience. 2. Overusing lazy loading, which can cause delays in loading essential content. 3. Failing to test across different devices and browsers.

How can I test the effectiveness of lazy loading on my site?

You can use tools like Google Lighthouse to analyze your site's performance. Look for metrics like loading time and user experience scores before and after implementing lazy loading.