This #sanitize helper will html encode all tags and strip all attributes that aren’t specifically allowed. It also strips href/src tags with invalid protocols, like javascript: especially. It does its best to counter any tricks that hackers may use, like throwing in unicode/ascii/hex values to get past the javascript: filters. Check out the extensive test suite.

<%= sanitize @article.body %>

You can add or remove tags/attributes if you want to customize it a bit. See ActionView::Base for full docs on the available options. You can add tags/attributes for single uses of #sanitize by passing either the :attributes or :tags options:

Normal Use

<%= sanitize @article.body %>

Custom Use (only the mentioned tags and attributes are allowed, nothing else)

<%= sanitize @article.body, :tags => %w(table tr td), :attributes => %w(id class style)

Add table tags to the default allowed tags

Rails::Initializer.run do |config|
  config.action_view.sanitized_allowed_tags = 'table', 'tr', 'td'
end

Remove tags to the default allowed tags

Rails::Initializer.run do |config|
  config.after_initialize do
    ActionView::Base.sanitized_allowed_tags.delete 'div'
  end
end

Change allowed default attributes

Rails::Initializer.run do |config|
  config.action_view.sanitized_allowed_attributes = 'id', 'class', 'style'
end

Source Code

# File action_view/helpers/sanitize_helper.rb, line 51
def sanitize(html, options = {})
  self.class.white_list_sanitizer.sanitize(html, options)
end