У вашего броузера проблема в совместимости с HTML5
EZkeys has been updated to version 1.1. It has some great new features like record mode and the ability to apply the preset midi sequences to your own chord structure. I show how this can be done quickly to get the basis of a song down in very little time.
You could always use this midi on any VST/AU track, so you are not limited to just a piano.