html + javascript automations = [mechanize + ?? ] or something else?

[John]

I have to write a spyder for a webpage that uses html + javascript. I
had it written using mechanize
but the authors of the webpage now use a lot of javascript. Mechanize
can no longer do the job.
Does anyone know how I could automate my spyder to understand
javascript? Is there a way
to control a browser like firefox from python itself? How about IE?
That way, we do not have
to go thru something like mechanize?

Thanks in advance for your help/comments,
--j