I have e very specific test setup in mind. I would like to start a web-browser that understands Javascript and can use HTTP proxy, point it to a URL (ideally by specifying it in the command line along with the proxy config), wait for the page to load while listening (in the proxy) requests are generated as web-page is rendered and Javascript is executed, then kill the whole thing and restart.

I don't care about how the page renders graphically at all.

Which browser or tool should I use for this?

Ideally it should be something self-contained that doesn't require installation (just an EXE file that runs from command line). Lynx would have been ideal but for the fact that it doesn't support JS. It should have as small memory footprint as possible.