Well my first thought is that there are a million instructions to step through before you get to the one you want, or before something interesting happens, so you would tear your hair out in frustration before then. My second thought is, I did this for some reason, and a million alerts flowing by for you to look at manually would be just as frustrating as a million breakpoints, so maybe there aren't a million, maybe there are only a thousand and it's manageable. Third thought; if you want to implement uvw = bp, injecting breakpoint instead of alert, that's fine with me. I imagine it would be a copy of the trace code but injecting something different. I'm working on some other things but they don't touch startwindow.js. You probably want to have a local snapshot to work with, already deminimized, so the line numbers mean something, then browse again with uvw = bp. Is there something specific you're trying to track down? I'm over here messing with the possibility of downloading all the js files and css files in parallel in the background, and not really sure if it's a good idea anyways, whether the performance improvements (if any) are worth the increase in code complexity. Trouble is, there's no way to know except to implement it an find out. Karl Dahlke