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GitHub User: picklepumpers
I'm not sure if it's changed since this 'cast came out but I had to do several more steps or the AJAX doesn't work:
Next you need to add ", :remote => true" to the end of the form_tag line in your partial file:
<%= form_tag products_path, :method => 'get', :id => "products_search", :remote => true do %>
Hopefully that helps anyone having problems following your mostly excellent tutorial.