module Loofah::HTML5::Scrub

def scrub_attribute_that_allows_local_ref(attr_node)
  return unless attr_node.value
  nodes = Crass::Parser.new(attr_node.value).parse_component_values
  values = nodes.map do |node|
    case node[:node]
    when :url
      if node[:value].start_with?("#")
        node[:raw]
      end
    when :hash, :ident, :string
      node[:raw]
    end
  end.compact
  attr_node.value = values.join(" ")
end