function doCalc() {
    var spread = FpSpread("FpSpread1");
        var roco = spread.GetRowCount();
    var total = 0;
    for (var i = 0; i < roco - 1; i++) {
       var value = parseFloat(spread.GetValue( i, 0 ));
       if(!isNaN(value))
       total += value;
    }
    if (!isNaN(total))
       spread.SetValue(n-1, 0, total, true);
}