Webform Server does not support predictive input checking. However, Webform Server does support type checking when the user exits a field.
For instance, if a field is set to accept phone numbers in the #-
## format, the user will be able to enter any initial value into that field. However, once they shift focus to another item, the field will be highlighted as an error if the value does not match the template.
Parent topic: Differences Between Webform Server and IBM Forms Viewer