[youngnh]

feel free to correct me if I'm wrong, but I thought that GreaseMonkey scripts run on the same page, but in no way _replace_ the scripts a site serves.

what, I think, Stallman envisions is being able to use your local copy of Gmail instead of the one Google's serving you without any loss of functionality.

[arebop]

GreaseMonkey scripts can modify the page contents, and if only GreaseMonkey scripts could run before whatever JavaScript is included with the page could start, then it could completely replace the site's script rather than just modifying its behavior shortly after the site's script begins to run. I think so anyway, I haven't actually implemented this so I won't claim to know for sure that it can be done.

Chromium has this "early injection" feature for GreaseMonkey scripts, so that's one free browser for which it would be very easy to build Stallman's replacement feature. See the link I gave earlier in this thread and also http://www.mail-archive.com/[e-mail]... for some background.