PhoneGap is exactly this. The problem is that recognizing touch gestures and animating them in the browser is a non-starter for almost all applications today. I

PhoneGap is exactly this. The problem is that recognizing touch gestures and animating them in the browser is a non-starter for almost all applications today. If the browser reliably gave JS low-level touch events and animated at 60fps almost all of these problems would go away.