Right now it is possible to add custom code in the HTML of a Marketing form. After designing it with the editor, you can add some validations, visibility functions to show some fields on demand etc. Although it's still very simple and needs further work.

We are hugely missing the onChange event for a Lookup field in a Marketing Form. While the onChange does work as intended for a text field, the onChange on the Lookup field won't be detected when you select an item from the list, it will only fire when you click outside the field.

A situation where the event is needed on the lookupfield is when you have 2 lookups: a Country lookup field and a Province lookup field you want to add in a Marketing form. You add them, and since the Province is dependant on the Country field, you only want to show it when the Country selected has province values. You prepare a simple visibility JavaScript function that detects when the Country field changes (from null to an item value, or from an item value to another) and the function will work as intended, but due to how the event is working, it won't be user-friendly since the onChange event will only fire when you click outside the field and not when you select the item in the list. Final user will find their experience with the form disturbed by this and us developers and businesses would be grateful if this could be improved.

Thanks