The field has a css class "geoArea".
I've tried the following lines of code
NWF$('.geoArea select option[title="My option title"]').prop("selected",true);
NWF$('.geoArea select').val(optValue); //optValue is a variable with the numeric value of the option I want to select
With both lines I'm able to apparently set to field to the value I want but when I save the form, the value is lost, so if I open it again the field is blank again.
If I select the value manually in the field, the value is save correctly.
Do you know if is there anything else I have to set to save my value when I save the form?