+UndoButton
    +UpField
    
    (gui '(+UpField) 30)
    +UpButton
    +Upd
    upd> method in existing classes. The following example uses
    +Upd to print updated values to standard error:
    
    (app)
    (default *Number 0)
    (action
       (html 0 "+Upd" "@lib.css" NIL
          (form NIL
             (gui '(+Upd +Var +NumField)
                '(prog (extra) (msg *Number))
                '*Number 8 )
             (gui '(+JS +Button) "Increment"
                '(inc '*Number) ) ) ) )
    +Url
    
   (gui '(+View +Url +TextField)
      '(and (port> (: home obj)) (pack "https://foo.net/" @))
      '((Url) (pack Url "/umc/adm.l?*PW=" (pw))) )
    (url URL . @)
    
    (gui '(+Rid +Button) "Contemporaries"
       '(url "!contemporaries" (: home obj)) )
    +Uppc
  
  "Upper case" (gui '(+Uppc +TextField) 30)