Unfortunately, no browsers support the device APIs yet. The specification seems to be in a rather early stage and can be found here - http://dev.w3.org/html5/html-device/
Ericsson Labs did a blog post with some snippets of code which is great, but there's no playground to try these out.
Another related question was asked on SO last year, but looks like things haven't changed much since.
However, you might find this interesting - nothing production worthy but still fun. This blog post talks about using the
