Jo (0.5.0) is a thin (~16K) candy shell for making HTML5 apps. Jo works with: PhoneGap, Chrome, Safari, Opera, FireFox, iOS, Android, BlackBerry 10, Tizen, & Windows Phone 8+. Features include skinnable UI widgets, a clean event model and a light data layer.
Saw this on BlackBerry 10 and Tizen. Basically, the x/y location reported doesn't match where your finger is; probably due to browser scaling.