Wiley Beginning ASP.NET 2.0 AJAX 978-0-470-11283-0 Manuale Utente

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Introduction 

to ASP.NET AJAX

Over the years, we developers have seen many changes in terms of how development occurs. We
have gone from terminal-based programming to PC-based programming to Windows-based pro-
gramming and to the Web. Now we are on the verge of another programming revolution — one
that will bring about more interactive user interfaces to web applications. This programming revo-
lution is brought to developers courtesy of a set of technologies that are generally known as AJAX
(Asynchronous JavaScript And XML). No longer will users see the annoying flash with the clicking
of a button to submit data. No longer will users lose the context of where they are located and be
thrown back up to the top of a page. With AJAX, developers can build applications that step out of
the traditional postback model of the Web, provide an improved user interface to users, and allow
developers to develop applications that are much friendlier to use.

This chapter looks at the following:

❑

ASP.NET development and how it led to AJAX

❑

What AJAX is and a high-level overview of some of its base technologies

❑

The advantages of AJAX

❑

What ASP.NET AJAX is

❑

Some things that it might not make sense to do with AJAX

Development Trends

If you have been developing for a while, like us old guys, you have gone through several itera-
tions of development — from terminals connected to mainframes and mini-computers to per-
sonal computers and then to client-server development. Client-server development allowed for the
minimization of back-end resources, network resources, and the front-end PC by sending only the
necessary data between back end and front end. Intelligent client-server development allowed for
building applications that were responsive to the user and made efficient use of network and back-
end resources. As the web development methodology took off in the late 1990s, we unfortunately

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