$(document).ready(function() {
  var str_close;
  if ($.cookie('siaLang') == 'ita') {
    str_close = 'Chiudi';
  } else if ($.cookie('siaLang') == 'eng') {
    str_close = 'Close';
  }
  $(".mess").append('<span class="msg_close">' + str_close + '</span>');
  $(".msg_close").click(function() { $(this).parent().slideUp() })
});