//Addacheckboxgriditemtoaformandrestrictittooneresponsepercolumn.varcheckboxGridItem=form.addCheckboxGridItem();checkboxGridItem.setTitle('Where did you celebrate New Years?').setRows(['New York','San Francisco','London']).setColumns(['2014','2015','2016','2017']);varcheckboxGridValidation=FormApp.createcheckboxGridValidation().setHelpText(“Selectoneitempercolumn.”).requireLimitOneResponsePerColumn().build();checkboxGridItem.setValidation(checkboxGridValidation);