$(document).ready(function() {
  if (document.getElementById("logoholidays") != null)
    setLogo();
});
var oo = false;
function setLogo() {
  if (oo)
    $("#logoholidays").animate({ opacity: 1 }, 2000, function() { setLogo() });
  else
    $("#logoholidays").animate({ opacity: 0.2 }, 2000, function() { setLogo() });
  oo = !oo;
}