Hi, I am new to Rails. Been struggle finding solution for soooo long. Too long I think. I have nested form: <div id="items"> <%= f.fields_for :items do |i| %> <%= render 'item_fields', :f => i %> <% end %> <div class="links"> <%= link_to_add_association '+ product', f, :items %> </div> </div> with item_fields partial: <td><%= f.select :product_id, Product.all.collect {|p| [p.name, p.id, {'data-unit_cost'=>p.sell_price}, { class: 'product-chosen', id: 'product-select'} %> </td> <td><%= f.input :sell_price, id: "price-input" %> </td> <td><%= link_to_remove_association image_tag("delete.png"), f %></td> and coffee script: $("#product-select").change -> unit_cost = $('#product-select :selected').data('unit_cost') $('#price-input').val(unit_cost) The idea is everytime product is selected, it store sell_price as value for sell_price input. What I get is: 1. If I use 'product-select' and 'price-input' as class, the result is, the second row will duplicating the value from first row. <https://lh3.googleusercontent.com/-NJC-6R77HFU/U2jinN52rXI/AAAAAAAAAA4/4H86Nfc8a_w/s1600/duplicate.png> 2. If 'product-select' and 'price-input' as id, the second row value is empty. <https://lh3.googleusercontent.com/-w1PPRLPdtsA/U2jju-lz40I/AAAAAAAAABE/Qkh69CcM5mc/s1600/Screen+Shot+2014-05-06+at+8.28.24+PM.png> Gem I use: Cocoon, Simple_form, Chosen. The behaviour is the same without using Simple_form and Chosen gems. I see that fields_for block will create hidden_field_id which I think could solve this, but I don't know how to access it and use it in script. Any help would be appreciated. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/8c85281a-b8aa-4e3f-9f61-93d05c98f704%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.