view

<%= form_tag({:controller => :post_comment, :action => :index}, :remote => true, :class => 'form-ajax') do -%>
<%= label_tag :名前 %>
<%= text_field_tag :name %>
<%= label_tag :内容 %>
<%= text_area_tag :content %>
<%= submit_tag "追加" %>
<% end %>

conotoller

def index

@name = params[:name]
@content = params[:content]

end

root

post 'post_comment/index', to: 'post_comment#index'