Communication between browser and a local process

Question

I have a web app that needs to communicate with a local .NET app that controls some specialized hardware. Basically, the main purpose of the web app is to acquire data from that hardware and post the data to a web server. The local .NET app could act like a mini web server using something like WebServiceHost listening on localhost. I think that would make the JavaScript happy, but different browsers seem to have different CORS requirements. Things like proxies and the need for an SSL cert complicate things. Is there an easier way to do this?