This goes along the same lines as the Elinks/mozilla suggestion w/getting an existing browser to do the javascript work for you, and you stated you wanted this on win32 -- I haven't done it myself, but i know that Win32::OLE can be used to control Internet Explorer, so you could access the rendered page post-javascript processing through that. The only thing i've personally done is:

  my $ie = Win32::OLE->new('InternetExplorer.Application');
  $ie->Navigate($url);
  $ie->{Visible} = 1;
[download]

I didn't need anything more than the above, so i didn't delve into this information yet, but it looked very promising:
perl.com: Automating Windows Applications with Win32::OLE
Simple Automation Module For Internet Explorer