What is Ajax?
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Ajay Sharma March 05, 2007
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We were getting a number of querries from our clients and friends, asking what is AJAX?
With the development of Microsoft's Live, everyone is going crazy
about AJAX. So, we at Xaprio Solutions thaught of publishing this small
article about AJAX, which will help you guys understand it better.
Like DHTML, LAMP, or SPA, Ajax is not a technology in itself, but a
term that refers to the use of a group of technologies together. In
fact, derivative/composite technologies based substantially upon Ajax,
such as AFLAX, are already appearing. The Term AJAX refers to
Asynchronous JavaScript and XML.
For a number of tasks, only small amounts of data need to be
transferred between the client and the server, allowing a number of
Ajax applications to perform almost as well as applications executed
natively on the user's machine. This has the effect that pages need
only be incrementally updated in the user's browser, rather than having
to be entirely refreshed.
"Every user's action that normally would generate an HTTP request
takes the form of a JavaScript call to the Ajax engine instead", wrote
Jesse James Garrett, in the essay that first defined the term. "Any
response to a user action that doesn't require a trip back to the
server -- such as simple data validation, editing data in memory, and
even some navigation -- the engine handles on its own. If the engine
needs something from the server in order to respond -- if it's
submitting data for processing, loading additional interface code, or
retrieving new data -- the engine makes those requests asynchronously,
usually using XML, without stalling a user's interaction with the
application."
Traditional web applications essentially submit forms, completed by
a user, to a web server. The web server does some processing, and
responds by sending a new web page back. Because the server must send a
whole new page each time, applications run more slowly and awkwardly
than their native counterparts.
Ajax applications, on the other hand, can send requests to the web
server to retrieve only the data that is needed, and may use SOAP or
some other XML-based web services dialect. On the client, JavaScript
processes the web server's response, and may then modify the document's
content through the DOM to show the user that an action has been
completed. The result is a more responsive application, since the
amount of data interchanged between the web browser and web server is
vastly reduced. Web server processing time is also saved, since much of
it is done on the client.
The earliest form of asynchronous remote scripting, Microsoft's
Remote Scripting, was developed before XMLHttpRequest existed, and made
use of a dedicated Java applet. Thereafter, remote scripting was
extended by Netscape DevEdge at around 2001/2002 by use of an IFRAME
instead of a Java applet.
I am working in http://www.xaprio.com. Xaprio Solutions is an India
based IT Company revolving in and around Outsourcing. We aims towards
the "Web Fulfillment" by developing and designing world class
applications and products and by taking the Web to Next Generation. |