The demo is non-functioning on an up to date Windows Phone. Sadly this is all too common. It's not hard to support IE10 & 11, but too many developers and companies simply don't bother even failing to account for the desktop edition.

Ignoring minority but still important browsers is like ignoring Macs ten years ago. I can understand why. If you're working on a Mac testing in IE means firing up a virtual machine, and that's a faff. It's harder the other way though...PC users have no access to OSX at all. But we're professionals, so let's support all the things :-)