// Lazy load images
// ex. <img data-src="/path/to/image.jpg" alt="">
function lazyLoad() {
  [].forEach.call(document.querySelectorAll('img[data-src]'), function(img) {
    img.setAttribute('src', img.getAttribute('data-src'));
    img.onload = function() {
      img.removeAttribute('data-src');
    };
  });
}

document.addEventListener('DOMContentLoaded', function() {
  lazyLoad();
});