added append polyfill

static/js/cookienotice.js

@@ -57,4 +57,29 @@ var CookieNotice = function(text, label, lifetime) {
     window.onload = function() {
         init();    
     };
-};
+};
+
+// Source: https://github.com/jserz/js_piece/blob/master/DOM/ParentNode/append()/append().md
+(function (arr) {
+    arr.forEach(function (item) {
+        if (item.hasOwnProperty('append')) {
+            return;
+        }
+        Object.defineProperty(item, 'append', {
+            configurable: true,
+            enumerable: true,
+            writable: true,
+            value: function append() {
+                var argArr = Array.prototype.slice.call(arguments),
+                    docFrag = document.createDocumentFragment();
+
+                argArr.forEach(function (argItem) {
+                    var isNode = argItem instanceof Node;
+                    docFrag.appendChild(isNode ? argItem : document.createTextNode(String(argItem)));
+                });
+
+                this.appendChild(docFrag);
+            }
+        });
+    });
+})([Element.prototype, Document.prototype, DocumentFragment.prototype]);