Funny script to make the 'img' tags flow

img_flow.js

(function() { 
    var body = document.getElementsByTagName("body")[0];
    var target_x = 10;
    var target_y = 10;

    var img_list = Array.prototype.slice.call(document.getElementsByTagName("img"), 0, 9);

    function img_iter(f) {
        for (var i in img_list) {
            if (img_list[i].style) {
                f(img_list[i])
            }
        }
    }

    img_iter(function(img) {
        img.style.position = "fixed";
    });

    cb = function() {
        var prev_x = target_x;
        var prev_y = target_y;
        img_iter(function(img) {
            var c_rect = img.getBoundingClientRect();
            var dx = prev_x - c_rect.left;
            var dy = prev_y - c_rect.top;
            prev_x = Math.floor(c_rect.left + dx * 0.2);
            prev_y = Math.floor(c_rect.top + dy * 0.2);
            img.style.left = prev_x + "px";
            img.style.top = prev_y + "px";
        });
    }

    body.onmousemove = function(e) {
        target_x = e.clientX + 10;
        target_y = e.clientY + 10;
    };

    return setInterval(cb, 30);
})();