[GuiA]

It's jsc (comes with Webkit) - it's present on Mac OS X by default in

/System/Library/Frameworks/JavaScriptCore.framework/Versions/A/Resources/jsc

You can just do:

sudo ln /System/Library/Frameworks/JavaScriptCore.framework/Versions/A/Resources/jsc /bin/jsc

To be able to invoke it directly from the command line.

[bitops]

That is extremely useful. Do you know if any testing libraries or other useful functionality have been built around this?

I suppose if you are a WebKit-only developer, this utility could have many useful applications.

[jrockway]

There's also mozrepl, which lets you evaluate code in Firefox from the command-line or Emacs.

[hchinchilla]

Thanks, I'll look how to get this working on linux.

[mbq]

At least Arch has `js`package which gives you js command to obtain JS shell; in fact it is just Mozilla's SpiderMonkey. Anyway, the best option for "standalone JS" is node, mainly because it has a sane way of importing code from other files.

[gpmcadam]

Alternatively, you could use Rhino Shell (https://developer.mozilla.org/en/Rhino_Shell) - it even supports tab completion!

[betterth]

My Chrome install on Windows has the same thing. I push ctrl+shift+c to load the developer tools, and click on console and it's a very similar tool to what he was using.