| AJAX
- A New Approach to Web
Applications
|
Introduction
Web
application designing has by far evolved in a number of ways since the time of
its birth. To make web pages more interactive various techniques have been devised
both at the browser level and at the server level. The introduction of XMLHttpRequest
class in the Internet Explorer 5 by Microsoft paved the way for interacting with
the server using JavaScript, asynchronously. AJAX, a shorthand for Asynchronous
Java And XML, is a technique which uses this MLHttpRequest object of the browser
features plus the Document Object Model and DHTML and provides for making highly
interactive web applications in which the entire web page need not be changed
by a user action, only parts of the page are loaded dynamically by exchanging
information with the server. This approach has been able to enhance the interactivity
and speed of the web applications to a great extent. Interactive applications
such as Google Maps, Orkut, Instant Messengers are making extensive use of this
technique. This report presents an overview of the basic concepts of AJAX and
how it is used in making web applications.
Creating Web applications has
been considered as one of the most exciting jobs under current interaction design.
But, Web interaction designers can't help feel a little envious of their colleagues
who create desktop software. Desktop applications have a richness and responsiveness
that has seemed out of reach on the Web. The same simplicity that enabled the
Web's rapid proliferation also creates a gap between the experiences that can
be provided through web applications and the experiences users can get from a
desktop application.
In the earliest days of the Web, designers chafed against
the constraints of the medium. The entire interaction model of the Web was rooted
in its heritage as a hypertext system: click the link, request the document, wait
for the server to respond. Designers could not think of changing the basic foundation
of the web that is, the call-response model, to improve on the web applications
because of the various caveats, restrictions and compatibility issues associated
with it.
But the urge to enhance the responsiveness of the web applications,
made the designers take up the task of making the Web work the best it could within
the hypertext interaction model, developing new conventions for Web interaction
that allowed their applications to reach audiences who never would have attempted
to use desktop applications designed for the same tasks. The designers' came up
with a technique called AJAX, shorthand for Asynchronous Java And XML, which is
a web development technique for creating interactive web applications. The intent
of this is to make web pages feel more responsive by exchanging small amounts
of data with the server behind the scenes, so that the entire web page does not
have to be reloaded each time the user makes a change. This is meant to increase
the web page's interactivity, speed, and usability. AJAX is not a single new technology
of its own but is a bunch of several technologies, each ourishing in its own right,
coming together in powerful new ways.
What is AJAX?
AJAX
is a set of technologies combined in an efficient manner so that the web application
runs in a better way utilizing the benefits of all these simultaneously. AJAX
incorporates:
1. standards-based presentation using XHTML and CSS;
2. dynamic
display and interaction using the Document Object Model;
3. data interchange
and manipulation using XML and XSLT;
4. asynchronous data retrieval using XMLHttpRequest;
5.
and JavaScript binding everything together.
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