The css portion, that maps css attributes over to objects, takes 2 minutes to run.
That's not the infinite loop, but it is intolerable nonetheless.
Browse www.stackoverflow.com with db3 and watch 2 minutes go by between

execute eb$qs$start
execution complete

The version we got was built to run and handle all situations, and be robust, but obviously not optimized.
Optimizing things is something I'm good at, but it's a lot of code doing something I'm not entirely familiar with, so I would be taking a big bite.
Could it be optimized and still be javascript? Is it primarily an algorithmic inefficiency?
Or would it have to be rewritten in C?
I hope the former, because turning all that into C would be a pain!
There's no real reason to mess with the css parser, that runs once and pretty fast,
but querySelectorAll compares every css directive against every node in the document, which is potentially an n^2 problem.

Karl Dahlke