var _POPUP_COST_FEATURES = ', left=20, top=20, resizable=no, scrollbars=no, menubar=no, toolbar=no, directories=no, location=no, status=no';
var _POPUP_FEATURES = 'width=320, height=256';

function link_popup(url, target, features) {
   features = features || _POPUP_FEATURES;
   features = features + _POPUP_COST_FEATURES;
   target = target || '_blank';
  var theWindow = window.open(url, target, features);
  theWindow.focus();
  return theWindow;
}

function event_popup_features(features) {//questa funzione mi serve per passare i parametri senza attivare la funzione
	return function(e) { 
		Event.stop(e);
		var obj= Event.element(e);
		if(obj.tagName!='a' && obj.tagName!='A'){obj=obj.up('a');}
		link_popup(obj.getAttribute('href'), obj.getAttribute('target') || '_blank', features);
	}
}