Anyone seen a Javascript interpreter in Python?

[Robert Oschler]

Only half-kidding.  Ever tried debugging some complex Javascript code that's
inserted by an XSL document for XML document processing?  If I woke up
tomorrow and all the mainline browsers incorporated a Python interpreter I
would have died and gone to heaven.  Maybe someone will write a Javascript
interpreter in Python and then we can modify it to do some Python level
excellence of traceback info.  (Yes I know about the Venkman debugger.)

thx