example.html.erb

# example entry form

<tr>
	<td class="f_right">Country</td>
	<td><%= country_select(:profile, :country, priority_countries=['United Kingdom','United States'])%></td>
</tr>

<tr>
	<td class="f_right">Location</td>
	<td>
		<%= observe_field :profile_country, :frequency=>0.5,
			:update=>"state_select",
			:url=> {:action=>'state_select', :only_path=>false},
			:with=>"'country=' + encodeURIComponent(value)" %>

		<div id="state_select">
		<%= state_select :profile, :location, country='UK' %>
		</div>
	</td>
</tr>


# and put this in a partial called _state_select.html.erb

<% if params[:country] == "United States" %>
<%= state_select :profile, :location, country='US' %>
<% elsif params[:country] == "United Kingdom" %>
<%= state_select :profile, :location, country='UK' %>
<% elsif params[:country] == "England" %>
<%= state_select :profile, :location, country='UK' %>
<% elsif params[:country] == "Ireland" %>
<%= state_select :profile, :location, country='IRELAND' %>
<% elsif params[:country] == "Scotland" %>
<%= state_select :profile, :location, country='SCOTLAND' %>
<% elsif params[:country] == "Wales" %>
<%= state_select :profile, :location, country='WALES' %>
<% elsif params[:country] == "India" %>
<%= state_select :profile, :location, country='INDIA' %>
<% elsif params[:country] == "Canada" %>
<%= state_select :profile, :location, country='CANADA' %>
<% elsif params[:country] == "Australia" %>
<%= state_select :profile, :location, country='AUSTRALIA' %>
<% elsif params[:country] == "Spain" %>
<%= state_select :profile, :location, country='SPAIN' %>
<% elsif params[:country] == "Uganda" %>
<%= state_select :profile, :location, country='UGANDA' %>
<% elsif params[:country] == "France" %>
<%= state_select :profile, :location, country='FRANCE' %>
<% elsif params[:country] == "Germany" %>
<%= state_select :profile, :location, country='GERMAN' %>
<% else %>
<%= text_field :profile, :location, :class=>"text" %>
<% end %>