conditionally load forge

authenticator.js

@@ -5,7 +5,14 @@ var Authenticator = exports.Authenticator || exports;
 var Unibabel = window.Unibabel; // || require('unibabel');
 var totp = window.totp; // || require('notp').totp;
 
-if (!window.crypto) {
+function loadForge() {
+  var script = document.createElement('script');
+  script.src = 'demo/bower_components/forge/dist/forge.min.js';
+  script.addEventListener('load', collectRandom);
+  document.body.appendChild(script);
+}
+
+function collectRandom() {
   document.addEventListener('mousemove', function (event) {
     var ev = event || window.event;
 
@@ -14,6 +21,14 @@ if (!window.crypto) {
   });
 }
 
+if (!window.crypto) {
+  if (!window.forge) {
+    loadForge();
+  } else {
+    collectRandom();
+  }
+}
+
 // Generate a key
 function generateOtpKey() {
   // 20 cryptographically random binary bytes (160-bit key)

index.html

@@ -93,7 +93,9 @@
     <script src="demo/bower_components/unibabel/unibabel.base32.js"></script>
 
     <!-- forge.* -->
+    <!--[if lt IE 11]>
     <script src="demo/bower_components/forge/dist/forge.min.js"></script>
+    <![endif]-->
 
     <!-- botp.totp -->
     <script src="demo/bower_components/botp/sha1-hmac.js"></script>