Rails 3.1 interdependent select dropdown lists

My database structure:

Countries(id,title,prefix)  
Towns(id,country_id,title)
Street(id,town_id,title)

I need to create开发者_开发技巧 interdependent select dropdown list: when i select Country, ajax loading towns from this country into select tag, and when i select Street, ajax loading street by selected town_id into street select tag. I want to ask whether there is a Rails way to generate this list. Thank you.

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I found some tutorial to make what you want :

• dependant dropdowns menus

• cascading menu