diff --git a/lib/ajax/ajaxcourse.js b/lib/ajax/ajaxcourse.js
index 0dfd6de5227..723140944ff 100644
--- a/lib/ajax/ajaxcourse.js
+++ b/lib/ajax/ajaxcourse.js
@@ -160,7 +160,7 @@ main_class.prototype.mk_button = function(tag, imgSrc, attributes, imgAttributes
         }
     }
     if (imgAttributes != null) {
-        for (var c=0; c<attributes.length; c++) {
+        for (var c=0; c<imgAttributes.length; c++) {
             image.setAttribute(imgAttributes[c][0], imgAttributes[c][1]);                
         }
     }