Default value using Autocompleter.local

I’m using recipe 7 from Rails Recipes to get really fast auto-
completion through Javascript.

I was previously using text_field_auto_complete which lets me define
a :value that appears in the field when the page is loaded - serving
as a default value.

I’d like to preserve this using the "<%= javascript_tag(“new
but I don’t know how to define a default value.