Video streaming had not play

I follow [Blog](https://developer.mozilla.org/en-US/docs/Web/API/WebRTC_API/Taking_still_photos) but when i compile my project , no error. Everything fine but video streaming is not playing. 

[Webrtc-Code](https://github.com/ali2210/WizDwarf/blob/master/js/video.js). Please help me to resolve this error
          OS : linux amd64
           browser : chrome
