I believe I recently built something to do exactly what you're describing for HTML, though it's C++ (but maybe a useful basis for a rust version - I don't know)

I believe I recently built something to do exactly what you're describing for HTML, though it's C++ (but maybe a useful basis for a rust version - I don't know). https://github.com/rthrfrd/webxx https://github.com/rthrfrd/webxx