diff --git a/_includes/polyfills.html b/_includes/polyfills.html
index 12ea0300d..ed6b6847f 100644
--- a/_includes/polyfills.html
+++ b/_includes/polyfills.html
@@ -1,8 +1,9 @@
-<script src='https://cdn.polyfill.io/v2/polyfill.min.js'></script>
+<script>(function(d,s){if(window.Promise&&[].includes&&Object.assign&&window.Map)return;var js,sc=d.getElementsByTagName(s)[0];js=d.createElement(s);js.src='https://cdn.polyfill.io/v2/polyfill.min.js';sc.parentNode.insertBefore(js, sc);}(document,'script'))</script>
+
 <!--[if lt IE 9]>{%comment%}
 {%endcomment%}<script src='//cdnjs.cloudflare.com/ajax/libs/nwmatcher/1.2.5/nwmatcher.min.js'></script>{%comment%}
 {%endcomment%}<script src='//cdnjs.cloudflare.com/ajax/libs/json2/20140204/json2.js'></script>{%comment%}
 {%endcomment%}<script src='//cdn.rawgit.com/gisu/selectivizr/1.0.3/selectivizr.js'></script>{%comment%}
 {%endcomment%}<script src='//cdnjs.cloudflare.com/ajax/libs/html5shiv/3.7.2/html5shiv.min.js'></script>{%comment%}
 {%endcomment%}<script src='//cdnjs.cloudflare.com/ajax/libs/respond.js/1.4.2/respond.js'></script>{%comment%}
-{%endcomment%}<![endif]--> 
+{%endcomment%}<![endif]-->