code: function init() {
          // find all elements with the class "appear"
          var els = document.getElementsByClassName('appear');
          var elsl = els.length;
          //  put html elements into an array object to work with
          for (var i = 0; i < elsl; i += 1) {
            // some images are revealed on a simple timeout, instead of
            // viewport appears. These delays appears must have
            // the appear class on them directly
            var delay = els[i].getAttribute('data-delay');
            if (delay) {
              delayAppear(els[i], delay);
            } else {
              nodes.push(els[i]);
            }
          }
        }
docs: function executed when dom is interactive