PyEcma is a Python JavaScript interperter.
>>> import pyecma
>>> js = r"""
... var a = 1 + 2;
... var b = 1 + 2 * 3;
... var c = (1 + 2) * 3;
... var d = (1 + 2) * (3 + 3);
... var e = (1 + 2 * 4) * ((2 + 1) * 2);
... """
>>> app = pyecma.parse(js)
>>> print(app.a)
3.0
>>> print(app.b)
7.0
>>> print(app.c)
9.0
>>> print(app.d)
18.0
>>> print(app.e)
54.0
>>> js = r"""
... function factorial (fac){
... if(fac > 1)
... return fac * factorial(fac-1);
... else
... return fac;
... }
... """
>>> app = pyecma.parse(js)
>>> print(app.factorial(5))
120.0
>>> js = r"""
... a = 1;
... function increment(){
... a++;
... }
... """
>>> app = pyecma.parse(js)
>>> print(app.a)
1.0
>>> app.a = 2
>>> app.a
2
>>> app.increment()
>>> print(app.a)
3.0