AJAX

AJAX = Asynchronous JavaScript And XML

Ajax is a set of Web development techniques using many Web technologies on the client side to create asynchronous Web applications.

With Ajax, Web applications can send data to and retrieve from a server asynchronously (in the background) without interfering with the display and behaviour of the existing page.

AJAX is not a programming language and not a single technology, but rather a group of technologies. HTML and CSS can be used in combination to mark up and style information.

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)

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

• The XMLHttpRequest Object
• The XMLHttpRequest object can be used to exchange data with a server behind the scenes.
• Create an XMLHttpRequest Object
• variable = XMLHttpRequest();
• XMLHttpRequest Object Methods

• AJAX - Send a Request To a Server
• The XMLHttpRequest object is used to exchange data with a server.
• Send a Request To a Server Methods



• GET

• POST

• OPEN A File