Another way to do this would be to use numba package to generate LLVM IR from Python bytecode (it supports a rich set of instructions including numpy stuff, has type inference, etc), and then run it in the browser via emscripten, with some adjustments to the IR if required.
And most general-purpose Python (e.g. dicts, most builtins, etc...) require running in "object mode" which is not standalone, it calls into the CPython API and thus requires an underlying CPython runtime.
So no, numba is not an other way to do that. shedskin[0] might be though.
Quick googling yields a related blog post: http://cyrille.rossant.net/numpy-browser-llvm/