$("document").ready(function() {

  $(".menu_item").mouseenter(function() {
    $(this).css({'background' : 'url("gfx/menu_on.jpg")'});
  });
  $(".menu_item").mouseleave(function() {
    $(this).css({'background' : 'url("gfx/menu_off.jpg")'});
  });
  
  $("#dati_aziendali").colorbox({width: "500px", height: "230px", iframe: "yes"});
  $("#link").colorbox({width: "900px", height: "600px", iframe: "yes"});
  $("#menu_prezzi_link").colorbox({width: "800px", height: "600px", iframe: "yes"});
  
});