function displayWindow(url, width, height)
{
  var Win = window.open(url, "displayWindow" , 'width=' + width + ',height=' + height + ',resizable=yes,scrollbars=yes,menubar=no');
}

function openTarget(form, features, windowName)
{
  var sztuk = form.sztuk_form.value;
  
  for(i = 0; i < sztuk.length; i++)
  {
    if(isNaN(sztuk.charAt(i)))
    {
      alert("Liczba sztuk wpisana niepoprawnie!");
      return false;
    }
  }

  if(!windowName) windowName = 'displayWindow';
  
  form.target = windowName;
  open('', windowName, features);

  return true;    
}