If you look at the Google Suggest, check out the way suggested terms update as you type, almost instantly. Another very fine example is the Google Map, Zoom in, use your cursor to grab the map and scroll around a bit. Again, everything happens almost instantly, with no waiting for pages to reload. Is not that amazing?
AJAX is not a technology. It's really several technologies, each flourishing in its own right, coming together in powerful new ways. Ajax incorporates:
o standards-based presentation using XHTML and CSS;
o dynamic display and interaction using the Document Object Model;
o data interchange and manipulation using XML and XSLT;
o asynchronous data retrieval using XMLHttpRequest;
The classic web application model works like this – Most user actions in the interface trigger an HTTP request back to a web server. The server does some processing – retrieving data, crunching numbers, talking to various legacy systems – and then returns an HTML page to the client.
What AJAX Does And Why You Should Consider Using It
AJAX allows web applications to perform partial page updates. Only the page elements that need to be updated are, thus providing a far more responsive page refresh mechanism. And if a web application developer is judicious in how pages are designed, there is almost no perceptible refresh delay.
AJAX can save bandwidth
Traditional Web applications deliver a tremendous amount of redundant information, particularly if pages are coded in old-fashioned HTML laden with tags. In such sites the amount of structuring and presentation markup required may be approximately as significant as that required to serve up the textual content of the page. However, following an AJAX design pattern, applications need to download page layout and structure items just once, and then update new data as needed, which could significantly reduce the application's bandwidth footprint per user session.
Companies using AJAX application
Google is making a huge investment in developing the Ajax approach. All of the major products Google has introduced over the last year – Orkut, Gmail, the latest beta version of Google Groups, Google Suggest, and Google Maps – are Ajax applications. (For more on the technical nuts and bolts of these AJAX implementations, check out these excellent analysis of Gmail, Google Suggest, and Google Maps.) Others are following suit: many of the features that people love in Flickr depend on Ajax, and Amazon's A9.com search engine applies similar techniques.
These projects demonstrate that Ajax is not only technically sound, but also practical for real-world applications. This is not another technology that only works in a laboratory. And Ajax applications can be any size, from the very simple, single-function Google Suggest to the very complex and sophisticated Google Maps.
All major browser platforms now support AJAX, including Internet Explorer, Mozilla FireFox, Netscape, Opera and Safari. There's also a move toward standardization of XML HTllJthe core component of AJAX.
Performing targeted information updates, or micro-updates, can substantially reduce network loads, in addition to faster interaction with live data. Benefits can be measured through total bytes transferred, total download time and steps / seconds to complete a task.
The increasing relevancy of AJAX is most obvious when looking at high-profile offerings, such as Google Maps and Salesforce.com, but what is not obvious is that it's quietly making inroads in large and small companies. Its rapid adoption signals a shift in the way enterprises will build and deliver future Web applications.
The biggest challenges in creating Ajax applications are not technical. The core Ajax technologies are mature, stable, and well understood. Instead, the challenges are for the designers of these applications: to forget what we think we know about the limitations of the Web, and begin to imagine a wider, richer range of possibilities.