For local websites, there are a couple of workarounds with Chrome in particular. I think creating a self-signed certificate and then adding it to Chrome should work to enable web-workers, but I haven't tested this. There's a chrome://flags thing to disable some security on localhost, but I don't know if this will enable web workers specifically. Anyway, check out this thread for things to try:
https://stackoverflow.com/questions/7580508/getting-chrome-t...