Most comments here seem to of the "Good no one should write a web page that accesses bluetooth and I don't care if you want to do that".
This is sad for me because I would like to be able to write web pages that talk to smart turbo trainers and other health devices.
Now you might say why not write a app to do that but personally I prefer accessing stuff from web pages.
I find apps restrictive as a user. For example there is no way to block ads in an app and often no way to zoom or select text.
Again you might be fine with that but I just wanted to offer an alternative opinion.