diff --git a/src/html/_preload_roboto.html.template b/src/html/_preload_roboto.html.template
index 6ac777eb8e..53431bb914 100644
--- a/src/html/_preload_roboto.html.template
+++ b/src/html/_preload_roboto.html.template
@@ -2,7 +2,7 @@
       if (navigator.userAgent.indexOf("Android") === -1 &&
           navigator.userAgent.indexOf("CrOS") === -1) {
         function _pf(src, type) {
-          const el = document.createElement("link");
+          var el = document.createElement("link");
           el.rel = "preload";
           el.as = "font";
           el.type = "font/woff2";