Not allow to save form if a fieldm is empty

[mmgiath]

How I can program a form if a field it's empty

does not allow to user ta save the form?

Thank you

[TundraSteve]

This seems odd, normally you'd allow a save of form because someone may not complete it in one sitting.  It's normally on the submit that mandatory fields are triggered.  Anyway, you can put a script on the presave and check the fields to determine if they're empty and handle accordingly