How to retrieve data via ajax request and display the result into the next tag? - ruby-on-rails-3

Question

I using jQuery and have the following code, it's a partial and I want to know how could I retrieve a specific data on the onchange method and display the result into the next tag. (inside the span tag)
NOTE: this select field are generated on-the-fly, so, I can have N id's.
<p class="fields">
<%= f.collection_select(:part_id, #parts, :id, :title, { :prompt => true } , { :onchange => "?" } ) %>
<span class='part_price'> _ _ _ _ </span>
<%= f.hidden_field :_destroy %>
<%= link_to_remove_fields "remove", f %>
</p>
Also I've created the method for this action (I don't know if this is right):
def retrieve_part_price
#price = Part.find(params[:id])
respond_to do |format|
format.html { redirect_to(items_path)}
format.json { render #price }
end
end
And put that on the routes.rb:
resources :items do
member do
get :update_part_price
end
end

Answer 1

Solved.
my partial:
<p class="fields">
<%= f.collection_select(:part_id, #parts, :id, :title, { :prompt => true } , { :onchange => "load_part_price_select(this.id, this.options[this.selectedIndex].value);" } ) %>
<%= f.label(:part_id, "Price: ") %>
<span class="price"></span>
<%= f.hidden_field :_destroy %>
<%= link_to_remove_fields "remove", f %>
</p>
application.js
function load_part_price_select(id, value) {
$('#' + id ).live('change',function() {
$.ajax({
url: '/parts/' + value + '/price',
type: 'get',
context: this,
dataType: 'script',
success: function(responseData) {
$(this).nextAll("span.price:first").html(responseData);
}
});
});
};
controller:
def price
#price = Part.find(params[:id])
respond_to do |format|
format.js { render :text => #price.price }
end
end