Over the last year or so, AJAX has taken the web development
approach to building dynamic web applications that behave less like the static
web pages we are used to and more like desktop applications.
At the heart of AJAX is the XmlHttpRequest object, a
component originally designed by Microsoft and used to provide the rich
an instance of XmlHttpRequest to send requests to the web server that generated
the page and then use the response to update part of the page, without the
browser having to reload everything. This can make the application a lot quicker;
instead of the entire page having to be transmitted and rendered, the browser
just fetches what is needed to update the current page.
Although the technologies that support AJAX-style web apps
have been around for years, they were not widely used until the introduction of
frameworks that made dealing with the extra complexity, not to mention
cross-browser differences, possible. Microsoft’s ASP.NET
AJAX Framework is one of the most recent, and has just been released as
version 1.0, following a year of pre-releases that used the code name “Atlas.”
This article shows you how to AJAX-enable an existing
ASP.NET web page by using Microsoft’s ASP.NET AJAX Extensions. The UpdatePanel
control provided by the framework makes it really easy to start with AJAX programming by defining the areas of the page you want to update independently without
a full page reload.
Once you have understood the basics, you will use an InnerWorkings coding challenge that
provides a sample AJAX-enabled bug tracking website to help you really
understand how to use the AJAX Extensions.