This proof-of-concept is a quick hack, and I had no chance to test it with a broad audience. It will probably fail for some users, but in general,
it should perform well. The code is Firefox-specific, although the approach itself is fully portable. My earlier
version works in multiple browsers, but only for about 50% of all users.
Weird results or no results? Ping me at lcamtuf@coredump.cx.