How do I use back button on windows phone

I've noticed we have the Windows Phone object. However when I export to the universal 8.1 windows, the windows phone behaviours (like triggered event on back button) do not work. I suppose that is made only for export for Windows Phone 8 and not as an universal windows 8.1 app?

I believe the Browser object's On back buttons Event works.

Thanks, will try it and update this thread.

Works on Windows Phone 8.1 ! Thanks a lot!