refactor app.js

public/index.html

@@ -71,6 +71,8 @@
     <script src="/script/external/katex-auto-render.min.js"></script>
     <script src="/script/external/notebook.min.js"></script>
 
+    <!-- Anonymous GitHub scripts -->
+    <script src="/script/utils.js"></script>
     <script src="/script/ng-pdfviewer.min.js"></script>
     <script src="/script/app.js"></script>
   </head>