Translating or Interpreting JavaScript from PHP

Any tips on running JavaScript code from PHP? I'm trying to run a javascript function and get its return value. This is a LOT easier in this case开发者_C百科 than translating it myself into PHP. Would Spidermonkey be good for this task, or something else?

UPDATE: On the other hand, if there's an app for translating the JavaSCcript into PHP once instead of just interpreting it, that might be better. So I'd be interested in recommendations on that front..

Thanks much

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What about:

J4P5 (quite basic) or V8JS (I haven't tried it)

I guess Spidermonkey can do the job as well... I have used J4P5 just very few so I can't suggest too much.