--- a/demo.html	Thu Jul 05 09:26:51 2018 +0800
+++ b/demo.html	Thu Jul 05 22:55:00 2018 +0800
@@ -5,7 +5,7 @@
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/2.3.2/css/bootstrap.min.css" integrity="sha384-MY3lqAyZWEjvYefTFTBYUN85pnmwAxdSjsX+8IqCP1N5VBzOIX6GNo1rUt9gz74C" crossorigin="anonymous">
 
     <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.2.4/jquery.min.js" integrity="sha384-rY/jv8mMhqDabXSo+UCggqKtdmBfd3qC2/KvyTDNQ6PcUJXaxK1tMepoQda4g5vB" crossorigin="anonymous"></script>
-    <script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js" integrity="sha384-FZY+KSLVXVyc1qAlqH9oCx1JEOlQh6iXfw3o2n3Iy32qGjXmUPWT9I0Z9e9wxYe3" crossorigin="anonymous"></script>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js" integrity="sha384-5DWzr9S4agqS3WKvPrhFKJagpYyHOBsf3/DxuDKORyqCv2sYer9c/ExdhPOL8CGh" crossorigin="anonymous"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.3.3/backbone-min.js" integrity="sha384-NNt9ocJfZhIg2c5PbM5G2a3tTaeXhEfqCHWHNB7htzaWKn8MwFkzVyGdzLA8QMX7" crossorigin="anonymous"></script>
 
     <script src="backbone.shard.js"></script>