AJAX - Asynchronous JavaScript and XML

by Shankar Patil, Prabhakar Mahale (Translator)

With the growth of Web applications, websites have been trying to make user interaction similar to that found in
desktop applications. The largest push is towards making Web interfaces more if data changes, say a new
email arrives in your inbox in GMAIL, the Web page should update and display the new email without reloading
the whole page.

The page should always be available to the user and always responsive to their input. While the DOM allows for such dynamic updates to occur, AJAX is an important group of technologies that allows a Web page to request more information from the server (such as an updated list of email in an inbox) without having to reload the whole page. Together, AJAX and the DOM can be used to create dynamic Web pages, and this chapter will introduce you to how that can be done.


AJAX stands for Asynchronous JavaScript and XML. It allows a Web page to make a request to a Web server for information using standard HTTP, but without reloading the page, and without automatically displaying the information returned from the server. These requests are all made programmatically, using JavaScript, and data communication is often done using XML, as JavaScript can easily parse this data. After receiving the data from
the server, the JavaScript script can use the returned data however it wishes. The requests can also be made in a
such a way that the JavaScript code does not have to wait for a reply from the server. Instead, the JavaScript code is
notified when the page has finished receiving the information.

In this way, the script can continue to perform useful
actions while the data downloads from the server – this makes the communication asynchronous to any action that the Web page is performing. It is important to realise that AJAX itself refers to a group of related technologies, not all of which are standardised, and not all of which need to be used at once. For instance, it can often be more convenient to communicate with the server using plain text rather than XML, and these communications need not occur asynchronously. Various other technologies are often employed in addition to those making up the AJAX name itself.

The original article that defined the term AJAX lists the following

• XHTML and CSS, which defines what is being displayed and how it is displayed.
• The Document Object Model, which allows us to programmatically alter the content and how it is
displayed.
• XML and XSLT, which is used to transfer data between the server and Web browser (using XML),
and to manipulate that data (using XSLT).
• XMLHttpRequest, which is the object used to communicate with the Web server over HTTP. This
object provides the asynchronous communication abilities.
• JavaScript, which is the programming language implemented in most Web browsers, and is used to
bring together.

Kindle Edition

Published May 25, 2021

About the author

Born on 8th August 1926, Shankar Patil was the most famous amongst the contemporary authors for his stories based mostly on the rural life. His language typically reflected the beauty of village life. Though he was a prominent story writer, he successfully tried his hands over the other forms of literature including the drama format. Initially, his themes appear to be simple but if studied at depth one is to see the many-fold dimensions involved in his writing process. Entertainment is not his solitary aim. His writing reflects his concern and commitment for the society. Instead of clinging to the rituals and traditions he aims at finding out new meanings for achieving better living standards. His writing has the base of a sensitive mind which is completely harmonious with the nature. He understands and accepts change as easily as one breathes under the normal circumstances.