diff --git a/src/js/bundle.js b/src/js/bundle.js
index f2d1436b8f7a02762c65ee1db286a8e338e4ed50..8012d152a9bba5a298b455b1b922df2deaaf2afd 100644
--- a/src/js/bundle.js
+++ b/src/js/bundle.js
@@ -34,7 +34,7 @@ ready(function () {
 
 
     // Clipboard
-    let clipboard = new ClipboardJS('.copy');
+    var clipboard = new ClipboardJS('.copy');
     clipboard.on('success', function (e) {
         setTimeout(function () {
             e.clearSelection();
diff --git a/src/js/main.js b/src/js/main.js
index ec5d4fc1fe722b5f8ffc42b3ae82863d506b44e1..d2b3426ba59f172d34579d80dd4dd1665e6e1529 100644
--- a/src/js/main.js
+++ b/src/js/main.js
@@ -21,7 +21,7 @@ ready(function () {
     // Language selector
     var languageSelector = document.getElementById("language-selector");
     languageSelector.onchange = function() {
-        let languageForm = document.getElementById("language-form");
+        var languageForm = document.getElementById("language-form");
         languageForm.submit();
         return true;
     };
@@ -32,14 +32,14 @@ ready(function () {
     menuLink.onclick = function(e) {
         e.preventDefault();
 
-        let layout = document.getElementById("layout");
+        var layout = document.getElementById("layout");
         if (layout.className.match(/(?:^|\s)active(?!\S)/)) {
             layout.className = layout.className.replace(/(?:^|\s)active(?!\S)/g , '');
         } else {
             layout.className += " active";
         }
 
-        let foot = document.getElementById("foot");
+        var foot = document.getElementById("foot");
         if (foot.className.match(/(?:^|\s)active(?!\S)/)) {
             foot.className = foot.className.replace(/(?:^|\s)active(?!\S)/g , '');
         } else {