Try it on mobile phone. The app is for Android by using the last camera of phone. I read (but have not tested) that for iPhone the first camera should be used.
Just in case somebody else was also looking for the relevant code as an example on how to include JS: You will find it in the Custom HTML of the form! For example: Form: _Professional, then self/properties/ Custom HTML/ then click Edit. May be that was obvious to everybody but me…