how to run javascript in emacs?

[Xah]

I want to run Javascript in a console with emacs. Does anyone have
suggestions on what's the solution?

Here's some detail... In perl/python/php, i can just write the code in
a buffer/file and run it with M-!. I would like to have something
similar for javascript. Basically, with the end result that i just
type in a buffer, save, press some button or command in emacs, and see
results. How can i do this?

I haven't much experience in coding javascript other than coding
simple sample scripts, and today i just downloaded Firebug in Firefox
3 but i don't want to have to switch to the browser.

The context is learning and experimenting with the language. I don't
need the DOM attached. Just need to for example write fibonacci or
prime generator and or other pure string manipulation functions with
js.

Since FF has a js engine...  is there a way to call the js interpreter
with operating system's command line? If so, that'd solve my problem.
(am not familiar with FF dev)

Thanks.

  Xah
∑ http://xahlee.org/

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