var domready = function() {
 var slideshows =  $(document.body).getElements("div.slideshow");
 var ss = [];
 for(var i=0;i<slideshows.length;i++) {
  ss.push(new Slideshow(slideshows[i]));
  ss[ss.length-1].start();
 }
};

window.addEvent('domready', domready);