Get the current response onSubmit
This code gives you the values for the last form response, is that what you're looking for ?
function myFunction() {
var formResponses = FormApp.getActiveForm().getResponses();
Logger.log(formResponses.length);
var formResponse = formResponses[formResponses.length-1];
var itemResponses = formResponse.getItemResponses();
for (var j = 0; j < itemResponses.length; j++) {
var itemResponse = itemResponses[j];
Logger.log('Last response to the question "%s" was "%s"',
itemResponse.getItem().getTitle(),
itemResponse.getResponse());
}
}