What are Preloading and Prefetching?
Preloading and prefetching are techniques used to load resources in advance to improve performance and user experience.
Difference Between Preload and Prefetch
| Feature | Preload | Prefetch |
|---|---|---|
| Purpose | Load critical resources early | Load future resources |
| Priority | High | Low |
| Usage | Current page | Next page/navigation |
| Timing | Immediately | Idle time |
Preloading
Preloading is used for critical resources needed for the current page. It tells the browser to load these resources early.
HTMLRead-only
1
Prefetching
Prefetching is used for resources that might be needed in the future, such as next pages or assets.
HTMLRead-only
1
When to Use Preload
- Critical CSS or fonts
- Hero images
- Important scripts
When to Use Prefetch
- Next page navigation
- Future user actions
- Low-priority resources
Best Practices
- Use preload only for critical resources
- Avoid overusing preload
- Use prefetch for future navigation
- Combine with caching strategies
Common Mistakes
- Preloading too many resources
- Using preload for non-critical assets
- Ignoring browser support and priorities
- Not testing performance impact
Conclusion
Preloading and prefetching are powerful tools for optimizing web performance. Using them correctly helps deliver faster load times and smoother navigation.