bootstrap 2 carousel random transition

<script type="text/javascript">
        var carouselContainer = $('.carousel');
        var slideInterval = 4000;

        function toggleCaption() {
            var caption = carouselContainer.find('.active').find('.carousel-caption');
            caption.slideToggle();
        }
        carouselContainer.carousel({
            interval: slideInterval,
            cycle: true,
            //pause: "hover"
        }).on('slid slide', toggleCaption).trigger('slid');
    </script>