# File lib/action_view/helpers/javascript_helper.rb, line 359
      def auto_complete_field(field_id, options = {})
        function =  "new Ajax.Autocompleter("
        function << "'#{field_id}', "
        function << "'" + (options[:update] || "#{field_id}_auto_complete") + "', "
        function << "'#{url_for(options[:url])}'"
        
        js_options = {}
        if options[:tokens] and options[:tokens].kind_of?(Array)
          js_options[:tokens] = "['#{options[:tokens].join('\',\'')}']"
        elsif options[:tokens]
          js_options[:tokens] = "'#{options[:tokens]}'" if options[:tokens]
        end
        js_options[:callback]   = "function(element, value) { return #{options[:with]} }" if options[:with]
        js_options[:indicator]  = "'#{options[:indicator]}'" if options[:indicator]
        function << (', ' + options_for_javascript(js_options) + ')')

        javascript_tag(function)
      end