Check which keys are being pressed with this simple piece of JavaScript.
Open the keys.html file in your browser, ensure JavaScript is enabled and the cursor is
in the input box, then press any keys and combinations of keys. The input box will show
you which ones are registered.
Be careful when holding down the Control key, as this key in combination with other keys will probably activate some function of your browser.
https://jsfiddle.net/507zLenw/
Click "1 release", then "v1.0", then ".zip". Tell your browser to open the zip file, then
navigate into key-ghosting-1.0 and open keys.html.