ASP.NET revolutionized web application development. The platform handles many of the complexities of creating web applications. And now ASP.NET AJAX takes the development platform even further. The line between rich client applications and traditionally less interactive browser-based applications is being further blurred. The Microsoft AJAX Library brings object-oriented programming to JavaScript development for modern browsers, and the ASP.NET 2.0 AJAX Extensions 1.0 make it easy to write rich web applications that communicate with the web server asynchronously. Again, the complexities are made easy by using ASP.NET. The new server controls that are part of ASP.NET AJAX make it simple to designate parts of the page to be updated automatically without making the user pause and wait while the data is refreshed. You can have partial page updates without writing a single line of code. Other new controls let you alert the user that background work is happening and designate regular intervals for updates to occur. And the ASP.NET AJAX Control Toolkit makes it easy to make your user interface really come to life with animations, modal dialogs, transition effects, and more.
This book is aimed at experienced ASP.NET developers looking to add AJAX to their applications, and experienced web developers looking to move to ASP.NET and AJAX together.
In this book, I assume that you already have an understanding of how ASP.NET works. For an in-depth discussion of ASP.NET, I recommend Professional ASP.NET 2.0, by Bill Evjen, et al. (Wrox, 2005). The focus here is on how you can extend ASP.NET applications to update portions of the page asynchronously and to add richer UI elements to a page. ASP.NET AJAX makes it easy to enrich your existing application or to design a new application to provide a better experience for users. The differences among modern browsers have been abstracted, allowing you to write to a common set of APIs and trust that the user will get the correct behavior whether they are using Internet Explorer, Firefox, or Safari.
If you know how to author ASP.NET pages, you can easily start using the Microsoft AJAX library to manipulate the browser’s Document Object Model and communicate with the server to update the user’s view of data without forcing them to wait for the entire page to be refreshed.