Replaces all missing images with images of kittens instead.

replace-missing-images-with-kittens.js

function kittenizeAllImages() {

  var images = document.getElementsByTagName('img');

  for (var i = 0; !!images[i]; i++) {
    if (!! images[i].dataset.notChecked)
      continue;
    checkImage(images[i]);
  }
}

function checkImage(originalImage) {
  var tempImage = document.createElement('img');
  tempImage.onerror = function () {
    var imageHeight = originalImage.height;
    var imageWidth = originalImage.width;

    originalImage.src = "http://placekitten.com/g/" + imageWidth + "/" + imageHeight;
  };
  tempImage.onload = function () {
    originalImage.dataset.checked = true;
  };
  tempImage.src = originalImage.src;
}

console.log("Kittenizing all images");

kittenizeAllImages();
setInterval(kittenizeAllImages, 1000);