Difference between JavaScript and Native lazy loading?
JavaScript lazy loading
JavaScript lazy loading uses intersectionObserver to detect elements in the viewport and lazy load them.
Pros:
- Supported by all major browsers
Cons:
- Lower performance compared to native
- Requires JavaScript
Browser Native lazy loading
Native lazy loading gives the best performance since it doesn't rely on JavaScript. This is supported in all browsers like Chrome, Firefox, Edge.
The threshold of lazy loading is determined by the browser based on several factors like connection speed, data saver mode, etc.
Pros:
- Fast, performant
- Less chance of conflicts
Cons:
- Higher thresholds
- Not supported in Safari and Opera
You can read more about native lazy loading here: https://web.dev/native-lazy-loading/