diff --git a/vendor/assets/javascripts/caret_position.js b/vendor/assets/javascripts/caret_position.js
index 094d504d4b..f811f7c073 100644
--- a/vendor/assets/javascripts/caret_position.js
+++ b/vendor/assets/javascripts/caret_position.js
@@ -164,7 +164,7 @@ $.fn.caretPosition = function(options) {
   }
 
   pPos = p.offset();
-  let position = {
+  var position = {
     left: pos.left - pPos.left,
     top: pos.top - pPos.top - clone.scrollTop()
   };