Neither one is required. You can use jQuery and it will work. There has been some discussion about MVVM frameworks being too heavy for web apps. But they do make some things easier. Before going with one, I'd do some web searches to find out how well they work with ASP.Net web forms.
>Thank you. So now I need to learn one and the other and then pick one. You like to torture me (kidding) <bg>
Craig Berntson
MCSD, Microsoft .Net MVP, Grape City Community Influencer