Autocompleting a text-box in rails

I need a field in a web form in rails named "country" that will autocomplete the user's answer based on a list of countries. E.g the User enters "Ameri" and the text box autocompletes the "ca". I need a list of countries and a way of autocompleting the form. Thanks.

Also I would like to have a field below that named "state" to provide only the states for the country specified so if the user chooses america the state list will have all t开发者_运维知识库he american states but if the user chooses another country it will provide the list of states for that country.

So where can I find a list of countries states and maybe even cities? How can I do autocomplete in rails? How can I have a field below the first one that autocompletes only the states for that country?

Thanks

Check out:

Autocomplete: http://jqueryui.com/demos/autocomplete/

Lists of geographic places including countries and states: http://autonomousmachine.com/posts/2009/4/1/carmen-a-rails-plugin-for-geographic-names-and-abbreviations