#5 Have stopwatch show elapsed time

[Remco Douma]

It now is not clear when the stopwatch is actually
running. Yes, you get a JavaScript alert when starting
it, but 4 hours later you don't remember you clicked
the "Clock on now" button or not. Besides, sometimes
you get a "Page not found" error, and you don't know
the amount of time you actually invested. So... a timer
would be nice.