I checked on http://caniuse.com/ but can't find anything about compatibility for the vibration API.
Which browsers support it?
Update [2014-03-07]: The Vibration API is now supported by Firefox, Chrome, and Opera. I've also made this information available on on caniuse.com.
Based on this article:
The Vibration API is still primarily unsupported. Firefox 16+ is currently the only browser with support for the API.