var nCondition = new GC.Spread.Sheets.ConditionalFormatting.Condition(GC.Spread.Sheets.ConditionalFormatting.ConditionType.dateCondition, {compareType: GC.Spread.Sheets.ConditionalFormatting.DateCompareType.before, expected: new Date(2012, 11, 31)});
var validator = new GC.Spread.Sheets.DataValidation.DefaultDataValidator(nCondition);
validator.type(GC.Spread.Sheets.DataValidation.CriteriaType.custom);
activeSheet.getCell(0, 0, GC.Spread.Sheets.SheetArea.viewport).validator(validator);
spread.options.highlightInvalidData = true;
activeSheet.setValue(0, 0, new Date(2012, 12, 12));