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Ajax introduction

AJAX Introduction:

AJAX is a developer's dream, because you can:
  • Update a web page without reloading the page
  • Request data from a server - after the page has loaded
  • Receive data from a server - after the page has loaded
  • Send data to a server - in the background

What is AJAX?

AJAX = Asynchronous JavaScript And XML.
AJAX is not a programming language.
AJAX just uses a combination of:
  • A browser built-in XMLHttpRequest object (to request data from a web server)
  • JavaScript and HTML DOM (to display or use the data)
Note: AJAX allows web pages to be updated asynchronously by exchanging data with a web server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.

How AJAX Works:

  • 1. An event occurs in a web page (the page is loaded, a button is clicked)
  • 2. An XMLHttpRequest object is created by JavaScript
  • 3. The XMLHttpRequest object sends a request to a web server
  • 4. The server processes the request
  • 5. The server sends a response back to the web page
  • 6. The response is read by JavaScript
  • 7. Proper action (like page update) is performed by JavaScript

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