If this is a web based app (rather than a local app based on web technologies, like webos or windows phone), you should move as much of the processing server si

If this is a web based app (rather than a local app based on web technologies, like webos or windows phone), you should move as much of the processing server side as possible. Aim to not use a client side framework at all, if you can get away with it. Obviously there's a trade off to be made between performance and development speed, but the more work you make the client do on a legacy device, the worst the user experience will be.