Slideshow in 12 lines of JavaScript

slideshow.js

 <script>
    /*
    A div with an id of 'slideshow' contains five images, the first of which is shown and the others are hidden using 
    a display style of none. Using JavaScript, create a simple slideshow that cycles through the images, displaying 
    each image for three seconds at a time, looping back to the first image when the end is reached. You cannot use 
    jQuery or any other library.
    */
    (function() {
        var images = document.getElementById("slideshow").getElementsByTagName("img");
        var currentIndex = 0;

        function rotate() {
            images[currentIndex].style.display = 'none';
            currentIndex = currentIndex+1 == images.length ? 0 : currentIndex+1;
            images[currentIndex].style.display = '';
        }

        setInterval(rotate, 3000);
    })();
</script>

Line 14 wants a modulo operation, bad! ;)

Not bad.