app.js

$(".deals_status :radio").on('change', function(){
       $(this).closest("form").submit();
	alert('ss');
});

controller.rb

  def deal_status

    deal_id = params[:deal_id]
    d = Deal.find_by_id(deal_id)
    d.state = params[:deal_status]
    d.save

  end

show.html.erb

					<%= form_tag("deal_status", :remote=>true, :id=>"deal" + d.id.to_s, :class => "deals_status") do %>

						<%= hidden_field_tag 'deal_id', d.id.to_s %>

						<%= radio_button_tag( :state, "won" ) %>
						<%= label_tag( :state_won, "Won" ) %>

						<%= radio_button_tag( :state, "lost" ) %>	
						<%= label_tag( :state_lost, "Lost" ) %>

						<%= radio_button_tag( :state, "pending" ) %>
						<%= label_tag( :state_pending, "Pending" ) %>

					<% end %>