sanitize

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 <a href="/rails/ActionView/Base">ActionView::Base</a> 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

Please note that sanitizing user-provided text does not guarantee that the resulting markup is valid (conforming to a document type) or even well-formed. The output may still contain e.g. unescaped ’<’, ’>’, ’&’ characters and confuse browsers.