diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index d1a1f4cf6..3a65bda5e 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -26,6 +26,13 @@ module ApplicationHelper
   def escape_unicode(javascript)
     if javascript
       javascript = javascript.dup.force_encoding("utf-8")
+
+      unless javascript.valid_encoding?
+        # work around bust string with a double conversion
+        javascript.encode!("utf-16","utf-8",:invalid => :replace)
+        javascript.encode!("utf-8","utf-16")
+      end
+
       javascript.gsub!(/\342\200\250/u, '
')
       javascript.gsub!(/(<\/)/u, '\u003C/')
       javascript.html_safe
diff --git a/spec/helpers/application_helper_spec.rb b/spec/helpers/application_helper_spec.rb
index 697f8d009..dbc92f925 100644
--- a/spec/helpers/application_helper_spec.rb
+++ b/spec/helpers/application_helper_spec.rb
@@ -2,7 +2,16 @@ require 'spec_helper'
 
 describe ApplicationHelper do
 
-  describe 'mobile_view?' do
+  describe "escape_unicode" do
+    it "encodes tags" do
+      helper.escape_unicode("<tag>").should == "\u003ctag>"
+    end
+    it "survives junk text" do
+      helper.escape_unicode("hello \xc3\x28 world").should =~ /hello.*world/
+    end
+  end
+
+  describe "mobile_view?" do
     context "enable_mobile_theme is true" do
       before do
         SiteSetting.stubs(:enable_mobile_theme).returns(true)