use the long form of $(document).ready()

templates/download.html

@@ -29,7 +29,7 @@
 <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/bootstrap-datetimepicker/4.17.47/js/bootstrap-datetimepicker.min.js"></script>
 
 <script type="text/javascript">
-    $(function () {
+    $(document).ready(function() {
         $('#start_time').datetimepicker({
             format:'YYYY-MM-DD HH:mm',
             sideBySide: true