As I pointed out this project is in it's infancy.
I merely tweeted about progress and it ended up here ;)
See [status](https://github.com/thlorenz/visulator#status) -- indicating in experimental stage.
I'm planning to allow loading binaries and also editing assembly (assembling it in the browser so the CPU emulator can run the opcodes).
I think an "emulator" that doesn't let you run your own code in it is not an emulator. It's only an interesting visualisation.