I have this code in my view:
<%= form_for :folder_name, :remote => true, :method => \"get\", :url => {:action => \"show_workflow_list\"}
try this
<%= f.select :foldernames, options_for_select(@folders, @folders.first), {}, {:onchange => remote_function(:method => :get, :url => {:action => 'show_workflow_list'}, :with => 'Form.Element.serialize(this)')}%>