There isn’t currently a way to access the onFormSubmit callback globally or via the UI, so you’d need to either replace it with an embedded form or use a workaround like detecting the hsvalidatedsubmit event (see below).
dadams:
Hi @Arlo_Gilbert The hsvalidatedsubmit event is triggered after the data in a HubSpot form passes validation. You can detect when that event is triggered, but anything you do after detecting the event would not block the submission from proceeding. The onFormSubmit function gets executed as part of the submission itself, so anything you include in that function will be executed before the form proceeds with the submission.