Introduction: The Error You've Seen a Thousand Times
You've seen "404 Not Found". But what does it actually mean? HTTP status codes are the language your browser uses to communicate with the server. Understanding them is crucial for debugging.
The Categories
- 2xx (Success): 200 OK. Everything worked.
- 3xx (Redirection): 301 Moved Permanently. The page has moved.
- 4xx (Client Error): 404 Not Found. The page doesn't exist. 403 Forbidden. You don't have permission.
- 5xx (Server Error): 500 Internal Server Error. The server broke.
How to Debug
Open Chrome DevTools -> Network tab. Refresh the page. Look at the status column. Any code above 399 indicates a problem.
Common Mistakes
- Ignoring 500 errors: They indicate bugs in your code or server issues.
- Not setting up custom 404 pages: A user-friendly 404 page improves UX.
Practical Exercise
Visit a non-existent page on a website. Note the status code. Then, find a page that redirects (301).
Tools & Resources
- HTTP Status Codes - Quick reference.
- Chrome DevTools - Network tab.
Conclusion
Status codes are your diagnostic tool. Learn them, and debugging becomes much easier.