AJAX

What is AJAX?

AJAX = Asynchronous JavaScript and XML.

AJAX is based on internet standards, and uses a combination of:

• XMLHttpRequest object (to retrieve data from a web server)
• JavaScript/DOM (to display/use the data)

The keystone of AJAX is the XMLHttpRequest object.

---

The XMLHttpRequest Object

All modern browsers support the XMLHttpRequest object.

The XMLHttpRequest object is used to exchange data with a server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.

Create an XMLHttpRequest Object

All modern browsers (Chrome, IE7+, Firefox, Safari, and Opera) have a built-in XMLHttpRequest object.

Syntax for creating an XMLHttpRequest object:

variable = new XMLHttpRequest();