Keyboard Command Key

var isCommandKey = function (keycode) {
	if (keycode < 47) {
		// Most Command Keys
		return true;
	} else if (keycode === 91 || keycode === 92 || keycode === 93) {
		// Windows keys
		return true;
	} else if (keycode === 144 || keycode === 145) {
		// Scroll Lock / Num Lock
		return true;
	} else if (keycode >= 112 && keycode <= 123) {
		// F keys
		return true;
	}

	return false;
}