function change_submit(pulldown){
  if (pulldown.options[0].selected == true) {
     alert("Bitte wählen Sie ...");
  }
  else {
     var presentSelection = pulldown.options[pulldown.options.selectedIndex].value;
     var allInfos = presentSelection.split(",");
     if (allInfos[1] == 'no')
       window.open(allInfos[0],'_top');
     else
        window.open(allInfos[0],'');
  }
}