none are my _perfect_ js shell
firebug is very good -- but there are some annoyances, such as often having to reload the window to get the shell activated once opened; and other shells have annoyances because they don’t feature up/down history like the firebug shell
and none of them allow you to exit the shell by typing “exit” -- you have to actually click something. or Ctrl-F4, I suppose.
At any rate, I thought poking at some of the JS shells might be an interesting project.