Detect whether browser has keyboard/arrow keys in web page

Question

I have a full-screen game in HTML+JavaScript, which uses the arrow keys as primary controls. This cannot be used on keyboardless Android devices (I haven\'t tested on iOS),

Answer 1

look for touch specific events such as touchstart or gesturestart and show the onscreen controls if detected.

http://developer.apple.com/library/safari/#documentation/AppleApplications/Reference/SafariWebContent/HandlingEvents/HandlingEvents.html

I am not sure if the system-info api has been implemented by any browsers: http://www.w3.org/TR/system-info-api/