function checkserialnum(serialnum)
{
	var serialnumber;
	var matchserialnum;
	serialnumber = serialnum.substring(0,6);
	if (serialnumber.toLowerCase() == "j06220" || serialnumber.toLowerCase() == "n17020" || serialnumber.toLowerCase() == "n15020")
	{
		return true;
	}
	else 
	{
		return false;
	}
}