AJAX stands for Asynchronous JavaScript with XML. ASP.NET AJAX is a framework built into ASP.NET 3.5. It helps to create efficient and interactive Web applications that conform to Web 2.0 standards. Let us look behind the history of AJAX.
Long ago, HTML (Hyper Text Markup Language) was the only used Markup language for building web pages. It is still the fundamental universal container for the Web. It was rendering more of Presentation rather than Data. HTML was power through HTTP (Hyper Text Transfer Protocol). HTTP abstracts the underlying TCP (Transfer Control Protocol) protocol which aids in Data transfer. It is a Protocol which Routers understand. It has operations like Get, Put, Post and Delete. HTML with HTTP formed the basis of Web. Then HTML slowly began to contain data and started acting as a service.
Then came the XML (eXtensible Markup Language), which represents Data in the format we need. XML acted for Data what HTML did for Web. People started thinking what if we ship XML instead of HTML. Exchanging XML over HTTP became a fashion and called as XML-HTTP. One practical example is RSS (Really Simple Syndication). XML-HTTP uses only Get operation of HTTP to access data. This formed the basis of AJAX.
Google Suggest was the first real application where people started realizing the Power of AJAX. ASP.NET AJAX framework was designed. It helped People to develop Web applications with Partial Page post-back. It helps us to update a fragment of a Page by receiving only the fragment of HTML under target. This looked like as if there were no post-back in Web applications. But behind the scenes, a fragment of HTML is posted back. All this magic was performed by the Update Panel in ASP.NET AJAX. The Update Panel encloses the fragment of HTML which needs a Partial Page Post-back. ASP.NET AJAX grew popular. It also enhanced the Client side experience for Developers.
ASP.NET AJAX was available as a separate installer for ASP.NET 2.0 web applications for VS 2005. It was then integrated to ASP.NET 3.5 in Visual Studio 2008. Apart from enabling Partial Update, AJAX also provides a set of rich Client Validation Controls like RequiredFieldValidator, RangeValidator etc, which were once the Server side Controls with “run at” attribute. This is a short History behind AJAX. In subsequent posts, we will see how to use AJAX for developing powerful Web applications.
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