Modernizr doesn't currently detect touch events in Windows (Phone) 8.
So, instead you can easily detect touch on iOS, Android, BlackBerry, Bada and Windows (Phone) 8 with the following:
var html = document.documentElement,
supportsTouch = 'ontouchstart' in window || navigator.msMaxTouchPoints;
html.className += ' touch';
html.className += ' no-touch';