While using getUserMedia API to access camera in desktop it will open web camera.of course it is help to video communication.but which camera is invoked when it is used in mobil
Unfortunately, you cannot (yet?) select this via the code.
Mozilla Firefox beta: When the user accepts to share camera, he/she also select what camera to share.
Chrome beta: I have only been able to use the face camera. Could be configurable, but I do not know how…
EDIT: In chrome it's possible to select the back facing camera programmatically. See the next answer by Probot in this thread.