Setting sound volume in HTML5 Video

I'm won开发者_如何转开发dering if it's possible somehow to play a video that has sound (in HTML5 + Video-Tag) without sound so that the video starts to play automatically without sound - and switches on the sound on mouseover for example.

---

foo.muted = true

http://www.w3.org/TR/html5/video.html#dom-media-muted