diff --git a/app/assets/javascripts/app/lib/app_post/task_manager.js.coffee b/app/assets/javascripts/app/lib/app_post/task_manager.js.coffee
index 4d5d77d82..8e0238b71 100644
--- a/app/assets/javascripts/app/lib/app_post/task_manager.js.coffee
+++ b/app/assets/javascripts/app/lib/app_post/task_manager.js.coffee
@@ -271,8 +271,12 @@ class _taskManagerSingleton extends App.Controller
     )
     @allTasks = allTasks || []
 
-    $('#content_permanent_' + key ).html('')
-    $('#content_permanent_' + key ).remove()
+    try
+      $('#content_permanent_' + key ).html('')
+      $('#content_permanent_' + key ).remove()
+    catch
+      @log 'notice', "invalid key '#{key}'"
+
 
     delete @workersStarted[ key ]
     delete @workers[ key ]
@@ -304,8 +308,11 @@ class _taskManagerSingleton extends App.Controller
 
     # release tasks
     for task in @allTasks
-      $('#content_permanent_' + task.key ).html('')
-      $('#content_permanent_' + task.key ).remove()
+      try
+        $('#content_permanent_' + task.key ).html('')
+        $('#content_permanent_' + task.key ).remove()
+      catch
+        @log 'notice', "invalid key '#{key}'"
 
       delete @workersStarted[ task.key ]
       delete @workers[ task.key ]
diff --git a/app/assets/javascripts/app/lib/app_post/utils.js.coffee b/app/assets/javascripts/app/lib/app_post/utils.js.coffee
index 9d6af70f2..e181401e1 100644
--- a/app/assets/javascripts/app/lib/app_post/utils.js.coffee
+++ b/app/assets/javascripts/app/lib/app_post/utils.js.coffee
@@ -193,4 +193,4 @@ class App.Utils
 
   # cleanString = App.Utils.htmlAttributeCleanup( string )
   @htmlAttributeCleanup: (string) ->
-    string.replace(/(\!|\s|\r|\t|,|\.|\?|"|'|\^|#)/g, '')
+    string.replace(/(\!|\s|\r|\t|,|\.|\?|"|'|\^|#|=|\(|\)|\$)/g, '')
diff --git a/public/assets/tests/html-utils.js b/public/assets/tests/html-utils.js
index b45ba55bd..c3bd0174a 100644
--- a/public/assets/tests/html-utils.js
+++ b/public/assets/tests/html-utils.js
@@ -592,6 +592,11 @@ test( "check attibute validation", function() {
   verify  = App.Utils.htmlAttributeCleanup( string )
   equal( verify, result, string )
 
+  string = 'abc()=$'
+  result  = 'abc'
+  verify  = App.Utils.htmlAttributeCleanup( string )
+  equal( verify, result, string )
+
 
 });