Web developmentBeginner

AJAX & Async Requests

Update the page without a full reload.

Learn the request lifecycle from XMLHttpRequest to fetch, handle JSON, forms, errors, CORS, polling and streaming, and build a live search feature.

10 lessons 26 hours Certificate included Self-paced

Start the first lesson View curriculum

Reviewed and updated October 2026 · Free to start

What you will learn

By the end, you can do this.

Make and cancel requests with fetch
Handle loading, error and empty states
Debug CORS and status-code mistakes
Build a debounced live search

Curriculum

10 lessons in 1 module

290 practice drills included for extra repetition

0/10 complete

01The request lifecycleFollow a request from user action to rendered response. Challenge 11 min 02XMLHttpRequestRead legacy XHR code and understand the event model. Challenge 12 min 03fetchUse the promise-based API with options for methods and headers. Challenge 13 min 04JSON APIsValidate response shapes before trusting them. Challenge 12 min 05Forms without a reloadSubmit forms with fetch and render field errors. Challenge 13 min 06Error handlingSeparate network, HTTP, parse and application errors. Challenge 13 min 07CORSUnderstand preflight, allowed origins and credentialed requests. Challenge 13 min 08Polling and streamingChoose polling, long polling or server-sent events for live data. Challenge 13 min 09Caching and cancellationAvoid duplicate requests with caching and cancel stale ones. Challenge 13 min 10Build live searchCombine debounce, abort, loading states and accessible results. Challenge 20 min

Certification

Finish the course. Prove the skill.

Complete every lesson, then pass a timed assessment to earn the AJAX & Async Requests Certificate. Each credential has a unique ID and a QR code that resolves to a live public record.

10 randomized questions
30 minute limit · 80% to pass
3 attempts per enrolment
Verifiable by QR or credential ID

Certification details Verify a credential

Pro members get five certification attempts and unlimited timed mock exams. Compare Pro

EduByte.tech

EduByte · Skills certificationIssued 26 Oct 2026

This certifies that

Your name

has successfully completed the assessed program

AJAX & Async Requests

Make and cancel requests with fetchHandle loading, error and empty statesDebug CORS and status-code mistakes

AJAX & Async Requests

By the end, you can do this.

10 lessons in 1 module

Finish the course. Prove the skill.

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