How does a XFA script behave in an XDP file, based on the XFA script...

This is how a XFA script behaves in an XDP file, based on the XFA script event "validationState"1. The validationState event occurs when a field value changes and the field needs to be validated. The script in this event can be used to check the validity of the field value and set the validation message accordingly. In adaptive forms, this script is mapped to the Validation expression property of the field, which can be used to define a custom validation rule using JavaScript.