The unix version of BeebEm, writtin in C++ and SDL, has been compiled into WebAssembly using Emscripen.

You can find a working example at [https://beeb.webassembly.link].

BeebEm 0.0.13 has support for Emulation of BBC model B, B+, Integra Board and Master 128 and support for Acorn 65C02, Acorn Z80, Torch Z80 and Acorn 80186 second processors. 

To build, follow the guide at [https://kripken.github.io/emscripten-site/docs/getting_started/downloads.html] to install Emscripten. Then:

./reconf
automake --add-missing

emconfigure ./configure CXXFLAGS='-g -O3 -s USE_ZLIB=1 -s USE_SDL=2'
emmake make


To deploy as a WASM binary:

mkdir -p usr/local/share
cp -a data usr/local/share/beebem

cp src/beebem beebem.bc
emcc -O3 beebem.bc -o beebem.html --preload-file usr/local/share/beebem/ --use-preload-plugins -s TOTAL_MEMORY=256MB -s WASM=1 -s USE_SDL=2 -s USE_ZLIB=1

You will then have a .html .js .wasm and .data file.

The original BeebEm for Unix is at [http://beebem-unix.bbcmicro.com/]

PC Keyboard:
  F12 will bring up the menu
  Break key is BREAK

Mac keyboard:
  fn-F12 will bring up the menu (use fn-F1 etc. for the red function keys)
  fn-Backspace is BREAK (so shift-fn-backspace will !BOOT...)