diff --git a/cms/static/js/base.js b/cms/static/js/base.js
index c07cb53ccf..c626fa1b3f 100644
--- a/cms/static/js/base.js
+++ b/cms/static/js/base.js
@@ -411,7 +411,7 @@ function showFileSelectionMenu(e) {
 }
 
 function startUpload(e) {
-    files = $('.file-input').get(0).files;
+    var files = $('.file-input').get(0).files;
     if (files.length === 0)
         return;