I am attempting to post form data to a google spreadsheet. Currently, if the form is validated, then the following occurs:
if (validateForm === true) {
As Google Apps Script now has a ContentService that can return JSON responses it is possible to make ajax requests without using the hidden iframe. As the article author of the original solution I've published an updated version of this technique which includes an ajax example
Users may also want to consider switching to this new version as it utilises other new Google Apps Script Services, in particular: