diff --git a/common/lib/xmodule/xmodule/html_module.py b/common/lib/xmodule/xmodule/html_module.py
index ffd80d238b..20fda1e9f5 100644
--- a/common/lib/xmodule/xmodule/html_module.py
+++ b/common/lib/xmodule/xmodule/html_module.py
@@ -18,7 +18,7 @@ log = logging.getLogger("mitx.courseware")
 
 class HtmlModule(XModule):
     js = {'coffee': [resource_string(__name__, 'js/src/javascript_loader.coffee'),
-                     resource_string(__name__, 'js/src/collapsible.coffee')
+                     resource_string(__name__, 'js/src/collapsible.coffee'),
                      resource_string(__name__, 'js/src/html/display.coffee')
                     ]
          }