ON INPUT: The ABAP/4 module is called only if a field has the value other than the initial Value. This first value is determined by the field’s Data Type: blanks for character Fields, Zeroes for numeric. If the user modifies the Fields Value back to its initial value, ON INPUT does not trigger a call. ON INPUT: The ABAP/4 module is called only if a field has the value other than the initial Value. This first value is determined by the field’s Data Type: blanks for character Fields, Zeroes for numeric. If the user modifies the Fields Value back to its initial value, ON INPUT does not trigger a call.