AJAX Tutorial

AJAX = Asynchronous JavaScript and XML.

AJAX is not a new language — it is a technique that uses existing standards. Its biggest advantage is exchanging data with a server and updating parts of a page without a full reload.

XMLHttpRequest is the classic way to implement AJAX (modern code often uses the Fetch API).

Learning path

1. AJAX Intro
2. AJAX Example
3. Create XMLHttpRequest
4. XHR Request
5. XHR Response
6. readyState
7. AJAX ASP/PHP
8. AJAX Database
9. AJAX XML
10. AJAX JSON
11. More Examples

Prerequisites

• HTML and CSS basics
• JavaScript basics

What an AJAX app usually involves

• Present information with HTML + CSS
• Update the DOM with JavaScript
• Exchange data as XML / JSON
• Talk to the server asynchronously with XMLHttpRequest (or fetch)

TIP

This tutorial focuses on XMLHttpRequest so you can see the underlying flow. In everyday projects you can also use fetch() — the idea is the same: request → wait → update the page.

Next: AJAX Intro