Introduction

AJAX (Asynchronous JavaScript and XML) is a term coined by Jesse James Garrett of Adaptive Path. It stands for a combination of different technologies that help you communicate seamlessly with the server without the need for a page refresh. Ajax applications involve the following technologies:

• JavaScript for running the core Ajax engine

• The XmlHttpRequest object to communicate with the server

• A web presentation using HTML and CSS or XSLT

• DOM to work with the HTML structure

• XML and JSON for data interchange

The XmlHttpRequest object is used to post HTTP/HTTPS requests to the server. Most modern browsers have a built-in XmlHttpRequest object.

Note

JSON (JavaScript Object Notation) is a lightweight data interchange format and is increasingly used in Ajax applications. It is basically a collection of name/value pairs and can be used with different data types, such as a string, number, Boolean, arrays, and objects.

In a typical web application, the client submits data to the server for...