diff --git a/lib/html5_validators/active_model/helper_methods.rb b/lib/html5_validators/active_model/helper_methods.rb
index 3891772..381fa00 100644
--- a/lib/html5_validators/active_model/helper_methods.rb
+++ b/lib/html5_validators/active_model/helper_methods.rb
@@ -3,31 +3,31 @@ module Validations
     module HelperMethods
       def attribute_required?(attribute)
         self.validators.grep(PresenceValidator).any? do |v|
-          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:if, :unless]).empty?
+          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:if, :unless, :on]).empty?
         end
       end
 
       def attribute_maxlength(attribute)
         self.validators.grep(LengthValidator).select {|v|
-          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:maximum, :is]).any? && (v.options.keys & [:if, :unless, :tokenizer]).empty?
+          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:maximum, :is]).any? && (v.options.keys & [:if, :unless, :on, :tokenizer]).empty?
         }.map {|v| v.options.slice(:maximum, :is)}.map(&:values).flatten.max
       end
 
       def attribute_minlength(attribute)
         self.validators.grep(LengthValidator).select {|v|
-          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:minimum, :is]).any? && (v.options.keys & [:if, :unless, :allow_nil, :allow_blank, :tokenizer]).empty?
+          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:minimum, :is]).any? && (v.options.keys & [:if, :unless, :on, :allow_nil, :allow_blank, :tokenizer]).empty?
         }.map {|v| v.options.slice(:minimum, :is)}.map(&:values).flatten.min
       end
 
       def attribute_max(attribute)
         self.validators.grep(NumericalityValidator).select {|v|
-          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:less_than, :less_than_or_equal_to]).any? && (v.options.keys & [:if, :unless, :allow_nil, :allow_blank]).empty?
+          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:less_than, :less_than_or_equal_to]).any? && (v.options.keys & [:if, :unless, :on, :allow_nil, :allow_blank]).empty?
         }.map {|v| v.options.slice(:less_than, :less_than_or_equal_to)}.map(&:values).flatten.max
       end
 
       def attribute_min(attribute)
         self.validators.grep(NumericalityValidator).select {|v|
-          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:greater_than, :greater_than_or_equal_to]).any? && (v.options.keys & [:if, :unless, :allow_nil, :allow_blank]).empty?
+          v.attributes.include?(attribute.to_sym) && (v.options.keys & [:greater_than, :greater_than_or_equal_to]).any? && (v.options.keys & [:if, :unless, :on, :allow_nil, :allow_blank]).empty?
         }.map {|v| v.options.slice(:greater_than, :greater_than_or_equal_to)}.map(&:values).flatten.min
       end
     end
diff --git a/spec/features/validation_spec.rb b/spec/features/validation_spec.rb
index 9bed690..67b6491 100644
--- a/spec/features/validation_spec.rb
+++ b/spec/features/validation_spec.rb
@@ -100,6 +100,21 @@
       find('textarea#person_bio')[:minlength].should == '10'
     end
   end
+
+  context 'with validation context' do
+    background do
+      Person.validates_presence_of :name, :bio, {:on => :create}
+    end
+    after do
+      Person._validators.clear
+    end
+    scenario 'new form' do
+      visit '/people/new'
+
+      find('input#person_name')[:required].should be_nil
+      find('textarea#person_bio')[:required].should be_nil
+    end
+  end
 end
 
 feature 'item#new' do
@@ -202,4 +217,19 @@
       find('textarea#item_description')[:minlength].should == '10'
     end
   end
+
+  context 'with validation context' do
+    background do
+      Item.validates_presence_of :name, :description, {:on => :create}
+    end
+    after do
+      Item._validators.clear
+    end
+    scenario 'new form' do
+      visit '/items/new'
+
+      find('input#item_name')[:required].should be_nil
+      find('textarea#item_description')[:required].should be_nil
+    end
+  end
 end