Some things do keep in mind:
1. Very early stage. Runs better on Chrome.
2. If you think this sucks, you're probably comparing my code to Fabrice Bellard's Jslinux[2], and as Bellard is a genius his code (which is unfortunately still not available in readable form) is probably much better than mine. But progress is being made.
3. Still, the potential is there, soon it will be possible to have a somewhat standard programming stack and write GUI applications that run off a canvas, as I said in [3].
4. For Chrome there is a nice terminal emulator (hterm) I lifted from the Chromium source tree. The rest use textarea.
5. The code, of course: https://github.com/ubercomp/jslm32/
If anyone has questions, I'll be happy to answer them.
[1] http://news.ycombinator.com/item?id=3767410 [2] http://bellard.org/jslinux [3] http://news.ycombinator.com/item?id=3769486
EDIT: Added itens 4 and 5.