diff --git a/js/collapse.js b/js/collapse.js
index 92cc0bc76f..85347d5f51 100644
--- a/js/collapse.js
+++ b/js/collapse.js
@@ -69,7 +69,7 @@
     var complete = function () {
       this.$element
         .removeClass('collapsing')
-        .addClass('in')
+        .addClass('collapse in')
         [dimension]('auto')
       this.transitioning = 0
       this.$element.trigger('shown.bs.collapse')