Microsoft ASP.NET AJAX is a free framework designed to make
it easier to write modern AJAX-style applications using ASP.NET. There are two
parts to the framework – a cross-browser JavaScript library and a set of
server-side ASP.NET controls. The JavaScript library goes beyond simply
enabling AJAX apps and provides object-oriented extensions to JavaScript to
make it easier to write complex applications that need to process a lot of data
in the browser. On the server-side, a set of new and enhanced ASP.NET controls
make it possible to write AJAX applications by simply adding controls to a
page, just as with non-AJAX applications. In fact, you don not have to write a
single line of JavaScript to create a fully-featured AJAX application.
As well as ASP.NET AJAX itself, there are two other
downloads available to add AJAX functionality to your site. The AJAX
Futures CTP (Community Technical Preview) is a collection of new features
which will be added to the main AJAX Extensions framework in the future. The AJAX
Control Toolkit contains prewritten components like panels that can be
dragged around the page and rating controls to enable users to submit feedback.