This blog post has a great discussion on the different Ajax frameworks out. He only post frameworks which allow solid Ajax. Notice how Magic Ajax is the only completly free framework which can just be copied and pasted. Its also the only one that can do complete ajax across applications because ANYTHING on the panel becomes ajax. Please note that you can disable control by control. Its also the only framework we have been able to get to work in Rainbow 2.0. I know we can just use call back [ which i plan on using for hardcore rainbow core/modules] but we were looking for a nice free complete ajax project. Thanks to MA, rainbow portal .NET 2.0 will soon post an ajax version.
easy to use[ my 19 y/o cousin can copy and paste]
Makes everything ajax
supports both 1.1/2.0
Works with all major browswers
Link: Ajax Comparison