diff --git a/tutorial/js/build.xml b/tutorial/js/build.xml
index 348f229..73d535d 100644
--- a/tutorial/js/build.xml
+++ b/tutorial/js/build.xml
@@ -83,6 +83,7 @@
   
   <target name="clean">
     <delete dir="${build}" />
+    <delete dir="gen-js"/>
     <delete file="tutorial-js.jar" />
   </target>