Hi:

I've been using HTTrack extensively over quite a few websites and had found
myself with many "lost" pages due to javascript problems (such as complicated
functions).

I don't have much knowledge about C programming, but don't feel adding an
"external" parser wouldn't be a good idea. As an example, you may read the one
located in:

<http://lxr.mozilla.org/mozilla/source/js/narcissus/>

being the parser:

<http://lxr.mozilla.org/mozilla/source/js/narcissus/jsparse.js>

as you could read is GPLed, so I couldn't see any problem to make this great
program even better.