| AJAX | | | | incorporates: |
| Asynchronous JavaScript + XML, is not a new | | | | - standards-based presentation using XHTML and |
| technology or a new programming language, but a | | | | CSS; |
| new way to use existing standards. It is a term | | | | - dynamic display and interaction using the |
| coined in 2005 by Jesse James Garrett, which | | | | Document Object Model; |
| describes a "new" approach to using a number of | | | | - data interchange and manipulation using XML and |
| existing technologies together, including: HTML or | | | | XSLT; |
| XHTML, Cascading Style Sheets, JavaScript, The | | | | - asynchronous data retrieval using |
| Document Object Model, XML, XSLT, and the | | | | XMLHttpRequest; |
| XMLHttpRequest object. It is a new technique for | | | | - and JavaScript binding everything together. |
| creating better, faster, and more interactive web | | | | The classic web application model works like this: |
| applications | | | | Most user actions in the interface trigger an HTTP |
| When these technologies are combined in the | | | | request back to a web server. The server does |
| AJAX model, web applications are able to make | | | | some processing — retrieving data, crunching |
| quick, incremental updates to the user interface | | | | numbers, talking to various legacy systems — |
| without reloading the entire browser page. This | | | | and then returns an HTML page to the client. |
| makes the application faster and more responsive | | | | It’s a model adapted from the Web’s |
| to user actions. | | | | original use as a hypertext medium. |
| With AJAX, a JavaScript can communicate | | | | Although we are just beginning to realize its full |
| directly with the server, with the XMLHttpRequest | | | | potential, the proven success of famous |
| object. With this object, a JavaScript can trade | | | | AJAX-based projects like Google Maps, Google |
| data with a web server, without reloading the | | | | suggest or gmail are few real time examples |
| page. | | | | which signifies that this is not just another media |
| AJAX uses asynchronous data transfer (HTTP | | | | hype, but rather a promising technology that may |
| requests) between the browser and the web | | | | change web-applications as we know them. |
| server, allowing web pages to request small bits | | | | The biggest challenges in creating Ajax applications |
| of information from the server instead of whole | | | | are not technical. The core Ajax technologies are |
| pages. | | | | mature, stable, and well understood. Instead, the |
| The AJAX technique makes Internet applications | | | | challenges are for the designers of these |
| smaller, faster and more user-friendly. | | | | applications: to forget what we think we know |
| Ajax isn’t a technology. It’s really several | | | | about the limitations of the Web, and begin to |
| technologies, each flourishing in its own right, | | | | imagine a wider, richer range of possibilities. |
| coming together in powerful new ways. Ajax | | | | Ajax has changed the face of the web forever. |