Old TechnologiesLesson 50Free preview

JS AJAX

This lesson is part of JavaScript · All levels

Summary

AJAX (Asynchronous JavaScript And XML) is a technique of sending and receiving data to a server without reloading an entire page. Historically implemented with XMLHttpRequest objects, it is now more commonly used with the Promise-based Fetch API. Because the process is asynchronous, users can still interact with the page while waiting for the server's response.

Key points

AJAX updates some of the pages to make the user experience smoother
XMLHttpRequest is a classic object with open, send, and event onreadystatechange methods
Fetch API is a modern replacement for Promise-based
The server response is generally JSON, although the AJAX name refers to XML.

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