var werbung = new Array();
var periodical;
var size = 3;
var prevIndex = 0;
var nextIndex = 0;
var period = 7500;

var transitions = function() {
  prevIndex = nextIndex;
  nextIndex = (nextIndex + 1) % size;
  werbung[prevIndex].toggle().chain(function() {werbung[nextIndex].toggle();});
}

function startTransitions() {
  transitions();
  periodical = transitions.periodical(period);
}

function initializeWerbung() {
  for ( var ii = 0; ii < size; ii++ ) {
    werbung[ii] = new Fx.Slide('werbung-'+(ii+1), {mode: 'vertical'});
    werbung[ii].hide();
    $('werbung-'+(ii+1)+'-container').setStyle('visibility', 'visible');
  }
  werbung[nextIndex].toggle();
  startTransitions.delay(period);
}

window.addEvent('domready', initializeWerbung);