I've definitely considered that as a possibility, however part of the application is to discover (search for) files on your system, and then upload specific fil

I've definitely considered that as a possibility, however part of the application is to discover (search for) files on your system, and then upload specific files based on requests from other people. I was thinking that this would be slightly prohibitive in the web browser, at least from what I know from building Java applets and Flash based uploaders. If I were to do this in the browser, I would want to use purely JavaScript, but I'm unsure if this would be powerful enough for what I want to do.