Are there any javascript libraries that can render terminal output in a browser?
There are sevral options that I've found based on terminal emulation using Javascript:
The first option seems to be the closest solution to what you need.
https://github.com/drudru/ansi_up probably is what you need, it will render any termial output to html
I used term.js, bone.io, expres.io for terminal emulation. Its working pretty well.