GMail and other web applications have adopted a new technique coined Ajax (by Adaptive Path). It brings web applications a step away from the stateless web and closer to real applications. It’s harder to built applications with the applications, but it’s hot – and the most recent release of Rails (for Ruby) promises to make it much easier to do Ajax applications. Before you do too many Ajax applications, do think for a second.
Providing feedback in user interfaces is quite important. If you have a task, which may take a while, one of the ways to signal to the users, that the system is working, is by displaying a progress bar. If you don’t know how to make one, we do have one available for you.