window.addEvent('domready', function(){
var timer = 5; 
var periodical, dummy; 
var ajax = new Request({
  url: '/barre_ajax.php',
  method: 'get',
  onRequest: function() {
    $('barre_ajax').fade(0);
  },
  onSuccess: function(responseText, responseXML) {
    $('barre_ajax').innerHTML = responseText;
    $('barre_ajax').fade(1);
  }
});
var refresh = (function() {
  dummy = $time() + $random(0, 100);
  ajax.send(dummy); 
}); 
  periodical = refresh.periodical(timer * 3000, this);
  ajax.send($time());

});