How to determine which key was pressed on a Bluetooth keyboard using JavaScript in iOS 9.2 Safari when the keyup event object is empty?

Question

I tried this with 3 different Bluetooth keyboards on the iPad Pro, and I got the same result with them all. One was the Logitech CLEAR iPad Pro keyboard, one of which was an Apple wireless keyboard and the other was an iPad smart keyboard.

When checking an event object from a JavaScript event for the keyboard, no matter what key is pressed, I get no data in the event object to help me distinguish which key was pressed on the Bluetooth keyboard. Here is what I get from the event object:

{ ... keyIdentifier: 0, keyCode: 0, key: undefined, charCode: 0, char: undefined, which: 0, ... } 

Of course, when I use the virtual keyboard in iOS, everything works fine, and I get the data I need.

Does anyone know about this? Or is the Bluetooth keyboard for the iPad just crippled when it comes to web applications ?: (