diff --git a/exampleSite/layouts/partials/foot_custom.html b/exampleSite/layouts/partials/foot_custom.html
index acbbb59..3a95d13 100644
--- a/exampleSite/layouts/partials/foot_custom.html
+++ b/exampleSite/layouts/partials/foot_custom.html
@@ -1,4 +1,4 @@
-<script src="https://yihui.name/js/math-code.js"></script>
+<script src="//yihui.name/js/math-code.js"></script>
 <script type="text/x-mathjax-config">
 MathJax.Hub.Config({
   tex2jax: {
@@ -9,4 +9,4 @@ MathJax.Hub.Config({
 </script>
 <script async src="//cdn.bootcss.com/mathjax/2.7.1/MathJax.js?config=TeX-MML-AM_CHTML"></script>
 
-<script async src="https://yihui.name/js/center-img.js"></script>
+<script async src="//yihui.name/js/center-img.js"></script>