var time = 3000;

    function slideSwitch(id) {
        var slideshow = $(id);
        var active = slideshow.getElement('.active');
        if (! active) {
            active = slideshow.getLast('.slide');
        }

        var next =  active.getNext('.slide');
        if (! next) {
            next = slideshow.getFirst('.slide');
        }

        active.addClass('last-active');
        active.fade('out');
        next.fade('in');
        active.removeClass('active');
        next.addClass('active');
    }

    window.onload = function() {
        if ($$(".slideshow")) {
            $$(".slideshow").each(function(slideshow) {

                var intervalId = null;

                var firstImage = slideshow.getFirst('.slide');
                firstImage.addClass('active');

                slideshow.getElements('.slide').each(function(e) {
                    e.setStyle('position', 'absolute');
                    if (! e.hasClass('active')) {
                        e.setStyle('opacity', '0');
                    }
                });

                clearInterval(intervalId);
                intervalId = setInterval("slideSwitch('" + slideshow.get('id') + "')", time);
            });
        }
    }