Check out the demo running at: https://riscv.org/software-tools/riscv-angel/
ANGEL is not under active development - it implements old draft versions of the RISC-V specs (~late 2014)
make, make sure you have GNU sed.
Start a webserver in the angel directory, e.g.
python -m SimpleHTTPServer 8000
Visit localhost:8000/run.html in your browser.