function handleCityChange(list, field)
{
    if (list.selectedIndex == (list.length - 1))
    {
        field.value = "";
        field.style.display = "inline";
    }
    else
    {
        field.value = list.value;
        field.style.display = "none";
    }
}


function validateCityField(source, args)
{
    cityField = $get(source.controltovalidate);
    if (cityField)
    {
        args.IsValid = ((cityField.style.display == 'none') || (args.Value != ""));
    }
}