The AJAX.NET Toolkit. Cool and easy to use as long as your created your .NET project using the AJAX template. But what about when you have an existing Visual Studio project and need to add AJAX.

I tried to do this recently and was getting the following error:

sys is undefined

Turns out there was quite abit that I needed to add to my web.config before I could start throwing cool AJAX controls in my pages.

The following article was instrumental in getting my new project up and running using AJAX

http://geekswithblogs.net/ranganh/archive/2007/07/15/113963.aspx