The core component of Ajax is XMLHttpRequest that enables execution of server side code without any page refresh. Ajax can send asynchronous requests to the server using JavaScript and XMLHttpRequest object and mapping functions that will be executed when response is received.

The beauty of Ajax is that, you can execute server side code with out any page refresh. Ajax is a world of “No Page Refresh” and rich user interface like windows applications. In traditional web applications, the user actions in the user interface invoke an HTTP request to the web server. Then the server will do lot of process on the server and then returns an HTML page to the client. In Ajax applications, the request is not for GUI or HTML, It is only for data. After fetching the data, you can create the user interface from the client using JavaScript and DOM. Ajax is a client-side technology and can interact with any server side technologies such as PHP, ColdFusion, ASP.net, JSP, and others.

Advantages of Ajax

Rich User Interface
Ajax allows us to create highly interactive user interface. A user don’t like page refresh continuously like typical webpages but they act more like desktop applications thus increasing the usability and interactivity.

Higher Performance
With reduction of page refresh comes reduction of loading times and faster response to actions. There’s no requirement of post back to HTML thus creating a refresh and reload of the whole page.

Who is using Ajax?
Huge web corporations like Yahoo, Google and MSN are making huge investments into develping new websites and converting their existing services to Ajax. The latest version of Google Groups, Google Live Search, Google Maps, Gmal, Flickr, Amazon’s A9, Live Mail, Yahoo mail all are Ajaxified and use Ajax extensively.

Ajax and Kliotech
We at kliotech have been using Ajax in our web development projects ever since the evolution of Ajax. Ajax is used extensively at several situations to avoid un-necessary page refresh, Simplify functionality and where a fast responsive interface is required.

With its allusion to the version numbers that commonly designate software upgrades, Web 2.0 was a trendy way to indicate an improved form of the World Wide Web, and the term has been in occasional use for several years. For examples — “DoubleClick was Web 1.0; Google AdSense is Web 2.0. Ofoto is Web 1.0; Flickr is Web 2.0″ — rather than definitions.

What is now termed “Web 1.0″ often consisted of static HTML pages that were updated rarely, if at all. They depended solely on HTML, which a new Internet user could learn fairly easily. The success of the dot-com era depended on a more dynamic Web where content management systems served dynamic HTML web pages created on the fly from a content database that could more easily be changed.

Proponents of the Web 2.0 approach believe that Web usage is increasingly oriented toward interaction and rudimentary social networks, which can serve content that exploits network effects with or without creating a visual, interactive web page. In one view, Web 2.0 sites act more as points of presence, or user-dependent web portals, than as traditional websites. They have become so advanced new internet users cannot create these websites; they are only users of web services, done by specialist professional experts.

Overview of Web 2.0 techniques

A website could be said to be built using Web 2.0 technologies if it features a number of the following techniques:

Technical

• Unobtrusive Rich Internet Application techniques (such as Ajax)
• CSS
• Semantically valid XHTML markup and/or the use of Microformats
• Advanced User Interface languages such as XUL and SVG
• Flash Remoting
• Syndication of data in RSS/Atom
• Aggregation of RSS/Atom data
• Clean and meaningful URLs
• Weblog publishing
• REST or XML Webservice APIs

General

• The site should not act as a “walled garden” - it should be easy to get data in and out of the system.
• Users usually own their data on the site and can modify at their convenience
• Mainly web-based - most successful Web 2.0 applications can be used almost entirely through a web browser
• Data returns should be dynamic, not static, changing depending on variables associated with the user’s query (e.g. keywords, location).