function $( obj )
  {
  return document.getElementById ( obj ) ;
  }
    
  function select_add ( obj )
    {
    if ( obj.id == 'type' ) 
      $('ajax').innerHTML = '' ;
      
    if ( $('type').value == '' )
      {
      $('ajax').innerHTML = '' ;
      $('add_button').style.display = 'none' ;
      $('search_button').style.display = 'none' ;
      return false ;
      } 
     
    advAJAX.post({
        url: "fields/" + $('type').value ,
        onSuccess : function(obj) { 
          $('add_button').style.display = 'inline' ; 
          $('search_button').style.display = 'inline' ;  
      
          var div = document.createElement("div")  ;
          div.innerHTML = obj.responseText ;
          $('ajax').appendChild(div);
          
          },
        onError : function(obj) { alert("Błąd: " + obj.status); }
    });
    }