function hideValidity()
{
    if (document.quotation.classType.value == "server")
    {
        showValidity.style.display="none";
        showValidityLine.style.display="none";
        document.quotation.years.options[0].selected=true;
    }
    else
    {
        showValidity.style.display="";
        showValidityLine.style.display="";
    }
}