Executing Javascript from Python

I have HTML webpages that I am crawling using xpath. The etree.tostring of a certain node gives me this string:

<script>
<!--
function escramble_758(){
  var a,b,c
  a='+1 '
  b='84-'
  a+='425-'
  b+='7450'
  c='9'
  document.write(a+c+b)
}
escramble_758()
//-->
</script>

I just need the output of escramble_758(). I can write a regex to figure out the whole thing, but I want my code to remain tidy. What is the best alternative?

I am zipping through the following libraries, but I didnt see an exact solution. Most of them are trying to emulate browser, making things snail slow.

• http://code.google.com/p/python-spidermonkey/ (clearly says it's not yet possible to call a function defined in Javascript)
• http://code.google.com/p/webscraping/ (don't see anything for Javascript, I may be wrong)
• http://pypi.python.org/pypi/selenium (Emulating browser)

Edit: An example will be great.. (barebones will do)

Using PyV8, I can do this. However, I have to replace document.write with return because there's no DOM and therefore no document.

import PyV8
ctx = PyV8.JSContext()
ctx.enter()

js = """
function escramble_758(){
var a,b,c
a='+1 '
b='84-'
a+='425-'
b+='7450'
c='9'
document.write(a+c+b)
}
escramble_758()
"""

print ctx.eval(js.replace("document.write", "return "))

Or you could create a mock document object

class MockDocument(object):

    def __init__(self):
        self.value = ''

    def write(self, *args):
        self.value += ''.join(str(i) for i in args)


class Global(PyV8.JSClass):
    def __init__(self):
        self.document = MockDocument()

scope = Global()
ctx = PyV8.JSContext(scope)
ctx.enter()
ctx.eval(js)
print scope.document.value