diff --git a/actionpack/CHANGELOG b/actionpack/CHANGELOG
index 5924b240da81fe417a1bad743d5a0c0b0989e893..aa1ddd1a08fcc9dde79fb68431a155f0be54b782 100644
--- a/actionpack/CHANGELOG
+++ b/actionpack/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Added simple alert() notifications for RJS exceptions when config.action_view.debug_rjs = true. [Sam Stephenson]
+
 * Added :content_type option to render, so you can change the content type on the fly [DHH]. Example: render :action => "atom.rxml", :content_type => "application/atom+xml"
 
 * CHANGED DEFAULT: The default content type for .rxml is now application/xml instead of type/xml, see http://www.xml.com/pub/a/2004/07/21/dive.html for reason [DHH]
diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb
index 95afff0e8457d858eaace6e4a2c1acd5ec2ca2c6..94e7a472329d3df9037e138dabdfd4a1673e40c1 100644
--- a/actionpack/lib/action_view/base.rb
+++ b/actionpack/lib/action_view/base.rb
@@ -162,6 +162,11 @@ class Base
     # shortly.
     @@local_assigns_support_string_keys = true
     cattr_accessor :local_assigns_support_string_keys
+    
+    # Specify whether RJS responses should be wrapped in a try/catch block
+    # that alert()s the caught exception (and then re-raises it). 
+    @@debug_rjs = false
+    cattr_accessor :debug_rjs
 
     @@template_handlers = {}
  
diff --git a/actionpack/lib/action_view/helpers/prototype_helper.rb b/actionpack/lib/action_view/helpers/prototype_helper.rb
index 1f6aa274dbad322262ef8b391294636ce9630aec..778161218080756ba93c094ee3f2fc79cef45599 100644
--- a/actionpack/lib/action_view/helpers/prototype_helper.rb
+++ b/actionpack/lib/action_view/helpers/prototype_helper.rb
@@ -370,12 +370,12 @@ def initialize(context, &block) #:nodoc:
         end
       
         private
-        def include_helpers_from_context
-          @context.extended_by.each do |mod|
-            extend mod unless mod.name =~ /^ActionView::Helpers/
+          def include_helpers_from_context
+            @context.extended_by.each do |mod|
+              extend mod unless mod.name =~ /^ActionView::Helpers/
+            end
+            extend GeneratorMethods
           end
-          extend GeneratorMethods
-        end
       
         # JavaScriptGenerator generates blocks of JavaScript code that allow you 
         # to change the content and presentation of multiple DOM elements.  Use 
@@ -425,7 +425,12 @@ def include_helpers_from_context
         # <script> tag.
         module GeneratorMethods
           def to_s #:nodoc:
-            @lines * $/
+            returning javascript = @lines * $/ do
+              if ActionView::Base.debug_rjs
+                javascript.replace "try {\n#{javascript}\n} catch (e) "
+                javascript << "{ alert('RJS error:\\n\\n' + e.toString()); throw e }"
+              end
+            end
           end
           
           # Returns a element reference by finding it through +id+ in the DOM. This element can then be
@@ -748,7 +753,7 @@ def append_to_function_chain!(call)
     class JavaScriptElementProxy < JavaScriptProxy #:nodoc:
       def initialize(generator, id)
         @id = id
-        super(generator, "$('#{id}')")
+        super(generator, "$(#{id.to_json})")
       end
       
       def replace_html(*options_for_render)
@@ -874,7 +879,7 @@ def append_enumerable_function!(call)
     
     class JavaScriptElementCollectionProxy < JavaScriptCollectionProxy #:nodoc:\
       def initialize(generator, pattern)
-        super(generator, "$$('#{pattern}')")
+        super(generator, "$$(#{pattern.to_json})")
       end
     end
   end
diff --git a/actionpack/test/controller/mime_responds_test.rb b/actionpack/test/controller/mime_responds_test.rb
index 6fcaaf302d8a3de69eb337b4c1256f950b247622..94273cf4aff3c874a69bac5ad5ec9cb8713dd82c 100644
--- a/actionpack/test/controller/mime_responds_test.rb
+++ b/actionpack/test/controller/mime_responds_test.rb
@@ -141,7 +141,7 @@ def test_using_defaults
 
     @request.env["HTTP_ACCEPT"] = "text/javascript"
     get :using_defaults
-    assert_equal "$('body').visualEffect(\"highlight\");", @response.body
+    assert_equal '$("body").visualEffect("highlight");', @response.body
 
     @request.env["HTTP_ACCEPT"] = "application/xml"
     get :using_defaults
diff --git a/actionpack/test/controller/new_render_test.rb b/actionpack/test/controller/new_render_test.rb
index 5bdb8ec7f8b0c997eb9ef1e5c505003ad7ae6b07..961269da59706c788159be360866f0bdc1ed5ba7 100644
--- a/actionpack/test/controller/new_render_test.rb
+++ b/actionpack/test/controller/new_render_test.rb
@@ -393,7 +393,7 @@ def test_render_xml
   def test_enum_rjs_test
     get :enum_rjs_test
     assert_equal <<-EOS.strip, @response.body
-$$('.product').each(function(value, index) {
+$$(".product").each(function(value, index) {
 new Effect.Highlight(element,{});
 new Effect.Highlight(value,{});
 Sortable.create(value, {onUpdate:function(){new Ajax.Request('/test/order', {asynchronous:true, evalScripts:true, parameters:Sortable.serialize(value)})}});
diff --git a/actionpack/test/template/prototype_helper_test.rb b/actionpack/test/template/prototype_helper_test.rb
index 253a8bac1c50d12e0f3d0f8ab8c2fa672bf03ed9..e0746f62e63290b3ebd4c8373285ecee0739b6d0 100644
--- a/actionpack/test/template/prototype_helper_test.rb
+++ b/actionpack/test/template/prototype_helper_test.rb
@@ -230,31 +230,31 @@ def test_to_s
   end
 
   def test_element_access
-    assert_equal %($('hello');), @generator['hello']
+    assert_equal %($("hello");), @generator['hello']
   end
 
   def test_element_proxy_one_deep
     @generator['hello'].hide
-    assert_equal %($('hello').hide();), @generator.to_s
+    assert_equal %($("hello").hide();), @generator.to_s
   end
 
   def test_element_proxy_assignment
     @generator['hello'].width = 400
-    assert_equal %($('hello').width = 400;), @generator.to_s
+    assert_equal %($("hello").width = 400;), @generator.to_s
   end
 
   def test_element_proxy_two_deep
     @generator['hello'].hide("first").clean_whitespace
-    assert_equal %($('hello').hide("first").cleanWhitespace();), @generator.to_s
+    assert_equal %($("hello").hide("first").cleanWhitespace();), @generator.to_s
   end
   
   def test_select_access
-    assert_equal %($$('div.hello');), @generator.select('div.hello')
+    assert_equal %($$("div.hello");), @generator.select('div.hello')
   end
 
   def test_select_proxy_one_deep
     @generator.select('p.welcome b').first.hide
-    assert_equal %($$('p.welcome b').first().hide();), @generator.to_s
+    assert_equal %($$("p.welcome b").first().hide();), @generator.to_s
   end
   
   def test_visual_effect
@@ -286,8 +286,8 @@ def test_collection_first_and_last
     @generator.select('p.welcome b').first.hide()
     @generator.select('p.welcome b').last.show()
     assert_equal <<-EOS.strip, @generator.to_s
-$$('p.welcome b').first().hide();
-$$('p.welcome b').last().show();
+$$("p.welcome b").first().hide();
+$$("p.welcome b").last().show();
       EOS
   end
 
@@ -299,10 +299,10 @@ def test_collection_proxy_with_each
       @generator.visual_effect :highlight, value
     end
     assert_equal <<-EOS.strip, @generator.to_s
-$$('p.welcome b').each(function(value, index) {
+$$("p.welcome b").each(function(value, index) {
 value.removeClassName("selected");
 });
-$$('p.welcome b').each(function(value, index) {
+$$("p.welcome b").each(function(value, index) {
 new Effect.Highlight(value,{});
 });
       EOS
@@ -312,10 +312,10 @@ def test_collection_proxy_on_collect
     @generator.select('p').collect('a') { |para| para.show }
     @generator.select('p').collect { |para| para.hide }
     assert_equal <<-EOS.strip, @generator.to_s
-var a = $$('p').collect(function(value, index) {
+var a = $$("p").collect(function(value, index) {
 return value.show();
 });
-$$('p').collect(function(value, index) {
+$$("p").collect(function(value, index) {
 return value.hide();
 });
     EOS
@@ -332,10 +332,10 @@ def test_collection_proxy_with_grep
     end
 
     assert_equal <<-EOS.strip, @generator.to_s
-var a = $$('p').grep(/^a/, function(value, index) {
+var a = $$("p").grep(/^a/, function(value, index) {
 return (value.className == "welcome");
 });
-var b = $$('p').grep(/b$/, function(value, index) {
+var b = $$("p").grep(/b$/, function(value, index) {
 alert(value);
 return (value.className == "welcome");
 });
@@ -352,10 +352,10 @@ def test_collection_proxy_with_inject
     end
 
     assert_equal <<-EOS.strip, @generator.to_s
-var a = $$('p').inject([], function(memo, value, index) {
+var a = $$("p").inject([], function(memo, value, index) {
 return (value.className == "welcome");
 });
-var b = $$('p').inject(null, function(memo, value, index) {
+var b = $$("p").inject(null, function(memo, value, index) {
 alert(memo);
 return (value.className == "welcome");
 });
@@ -364,7 +364,7 @@ def test_collection_proxy_with_inject
 
   def test_collection_proxy_with_pluck
     @generator.select('p').pluck('a', 'className')
-    assert_equal %(var a = $$('p').pluck("className");), @generator.to_s
+    assert_equal %(var a = $$("p").pluck("className");), @generator.to_s
   end
 
   def test_collection_proxy_with_zip
@@ -380,9 +380,17 @@ def test_collection_proxy_with_zip
 });
     EOS
   end
+  
+  def test_debug_rjs
+    ActionView::Base.debug_rjs = true
+    @generator['welcome'].replace_html 'Welcome'
+    assert_equal "try {\n$(\"welcome\").update(\"Welcome\");\n} catch (e) { alert('RJS error:\\n\\n' + e.toString()); throw e }", @generator.to_s
+  ensure
+    ActionView::Base.debug_rjs = false
+  end
 
   def test_class_proxy
     @generator.form.focus('my_field')
     assert_equal "Form.focus(\"my_field\");", @generator.to_s
   end
-end
\ No newline at end of file
+end