get Editing Contents
Returns the editing contents of this form element based on rules in the annotation (including JavaScript). The editing contents of a form field are the contents that are shown when the user is editing a form field. These contents may be different from the form field value in some situations. For example, when the form field is prepared to show numbers with a comma decimal separator, the editing contents should also contain a decimal comma so that the user can edit the form field without causing keystroke validation errors that would prevent input.
Return
Editing contents of this form element or null
if the field does not have editing contents (for example, because it doesn't have formatting scripts).