I personally don't use a serverside framework, with the Javascript toolkits there is really no need. I use Dojo for heavy duty apps and jQuery for lighter apps.

I personally don't use a serverside framework, with the Javascript toolkits there is really no need. I use Dojo for heavy duty apps and jQuery for lighter apps. I use a JSON library on the server side (for Java JAX-RS) that acts as the data and business logic layer. I like this because it separates the concerns of UI and business logic. It is faster to develop the UI because you are working in HTML, CSS and Javascript (make a change refresh look at firebug). It also allows me to stub the server side by writing json files. By the time I am done with the UI prototype, I have a very good definition of the services that I will need on the server side. The nice part about the loose coupled nature of building a web app this way is that you are not heavily invested in a server infrastructure, if you decide you no longer like your server language then you just start implementing new services in the language du jour.