Accessing camera (getUserMedia)

I would like to realize an HTML widget which uses the device camera. So that a user can take a photo.

Is it possible?

I tried using the navigator.getUserMedia() API (and the navigator.webkitGetUserMedia() API too) but it looks like it doesn't work. On my desktop browser it works properly.

Maybe should I have to add any key to the info.plist file?

Maybe have I forgotten something? Or do you know if there is another way to do this?

Thank you