On-Message Trigger in oracle form 11g

On-Message Trigger form level in oracle form 11g:-  this is common for all form.

DECLARE
BEGIN
   
   IF MESSAGE_TYPE = 'FRM' AND MESSAGE_CODE = 40400 
   THEN
      IF frmpkg_export.v_user_selected = 'D' 
      THEN
         message('Deleted Successfully', NO_ACKNOWLEDGE);
      ELSE
         message('Saved Successfully', NO_ACKNOWLEDGE);
      END IF;
   ELSIF MESSAGE_CODE = 40401 or MESSAGE_CODE = 40102 or MESSAGE_CODE = 40405 or MESSAGE_CODE = 40404 
   THEN
      NULL;
   ELSE
   message(MESSAGE_TEXT);
   END IF;
   

END;