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

rather than displaying the on-screen keyboard by default, add a button to toggle the display of the on-screen keyboard.

It might also be prudent to give the on-screen keyboard the ability to be resized.

Edit to answer question:

Keyboard should be hidden by default if most of your users are going to be on a computer,

Visible by default if most of your users are going to be on a mobile device.