diff --git a/src/static/js/ace.js b/src/static/js/ace.js
index 2f9c1e6da..bbf83c0e7 100644
--- a/src/static/js/ace.js
+++ b/src/static/js/ace.js
@@ -230,7 +230,7 @@ function Ace2Editor()
       // disableCustomScriptsAndStyles can be used to disable loading of custom scripts
       if(!clientVars.disableCustomScriptsAndStyles){
         $$INCLUDE_CSS("../static/css/pad.css");
-        $$INCLUDE_CSS(`../static/skins/${clientVars.skinName}/pad.css`);
+        $$INCLUDE_CSS("../static/skins/" + clientVars.skinName + "/pad.css");
       }
 
       var additionalCSS = _(hooks.callAll("aceEditorCSS")).map(function(path){
@@ -314,7 +314,7 @@ window.onload = function () {\n\
       var $$INCLUDE_CSS = function(filename) {includedCSS.push(filename)};
       $$INCLUDE_CSS("../static/css/iframe_editor.css");
       $$INCLUDE_CSS("../static/css/pad.css");
-      $$INCLUDE_CSS(`../static/skins/${clientVars.skinName}/pad.css`);
+      $$INCLUDE_CSS("../static/skins/" + clientVars.skinName + "/pad.css");
 
 
       var additionalCSS = _(hooks.callAll("aceEditorCSS")).map(function(path){