// Add a text item to a form and require it to be a number within a range.
var textItem = form.addTextItem().setTitle('Pick a number between 1 and 100?');
var textValidation = FormApp.createTextValidation()
.setHelpText('Input was not a number between 1 and 100.')
.requireNumberBetween(1, 100)
.build();
textItem.setValidation(textValidation);