html_options_for_form

# File actionpack/lib/action_view/helpers/form_tag_helper.rb, line 528
        def html_options_for_form(url_for_options, options, *parameters_for_url)
          options.stringify_keys.tap do |html_options|
            html_options["enctype"] = "multipart/form-data" if html_options.delete("multipart")
            # The following URL is unescaped, this is just a hash of options, and it is the
            # responsability of the caller to escape all the values.
            html_options["action"]  = url_for(url_for_options, *parameters_for_url)
            html_options["accept-charset"] = "UTF-8"
            html_options["data-remote"] = true if html_options.delete("remote")
          end
        end