# File lib/html5/filters/validator.rb, line 603
  def check_mime_type(token, tag_name, attr_name, attr_value)
    # XXX needs tests
    if not attr_value
      yield( {:type => "ParseError",
           :data => "attribute-value-can-not-be-blank",
           :datavars => {"tagName" => tag_name,
                "attributeName" => attr_name}})
    end
    if not is_valid_mime_type(attr_value)
      yield( {:type => "ParseError",
           :data => "invalid-mime-type",
           :datavars => {"tagName" => tag_name,
                "attributeName" => attr_name,
                "attributeValue" => attr_value}})
    end
  end