Add polyfill

assets/scripts/src/polyfill.js

@@ -0,0 +1,29 @@
+// Source: https://gist.github.com/paulirish/1579671
+(function () {
+  let lastTime = 0;
+  const vendors = ['ms', 'moz', 'webkit', 'o'];
+
+  for (let x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
+    window.requestAnimationFrame = window[`${vendors[x]}RequestAnimationFrame`];
+    window.cancelAnimationFrame = window[`${vendors[x]}CancelAnimationFrame`] || window[`${vendors[x]}CancelRequestAnimationFrame`];
+  }
+
+  if (!window.requestAnimationFrame) {
+    window.requestAnimationFrame = function (callback) {
+      const currTime = new Date().getTime();
+      const timeToCall = Math.max(0, 16 - (currTime - lastTime));
+      const id = window.setTimeout(
+        () => { callback(currTime + timeToCall); },
+        timeToCall,
+      );
+      lastTime = currTime + timeToCall;
+      return id;
+    };
+  }
+
+  if (!window.cancelAnimationFrame) {
+    window.cancelAnimationFrame = function (id) {
+      clearTimeout(id);
+    };
+  }
+}());

assets/scripts/src/sholo.js

@@ -1,6 +1,6 @@
 import Overlay from './overlay';
 import Element from './element';
-
+import './polyfill';
 
 /**
  * Plugin class that drives the plugin