A cute script to replace every image on a webpage with a kitten.

kittenfy.js

var images = document.getElementsByTagName("img");
for (var i = 0; i < images.length; i++) {
    var image = images[i];
    // images courtesy of placekitten.com
    image.src = 'http://placekitten.com/g/' + image.width + '/' + image.height;
}