Something

document.onkeyup = function(event)
{
	if (!event && window.event) event = window.event;
	if (String.fromCharCode(event.keyCode).toLowerCase() == 'n')
	{
		opena();
	}
	else if(String.fromCharCode(event.keyCode).toLowerCase() == 'n')
	{
		backa();
	}
}