_flight_fields.html.erb

<div class="well top_box">
  <h3>LESSON</h3>
    <%= f.association :flightlesson %>
	
    <div id="load_box">
	<p id="gradable_items"></p>
	<p id="scenarios"></p>
    </div>
</div>

flights_controller.rb

  def gradable_items_inputs
    @lesson = Flightlesson.find(params[:lesson])
    @graded_items = GradedItem.new
    @subjects = GradableSubject.all
    @grade_scale = current_school.gradescales.in_use.grade_scale_items.order("grade asc").collect{ |g| [g.name, g.grade] }
  end

flights_form.js.coffee

jQuery ->
# ready = ->

  f_lesson      = $("#flight_flightlesson_id")
  gi_container  = $("#gradable_items_container")
  load_box      = $("#load_box")
  lesson_tell   = $("#load_box #gradable_items")
  scenario_tell = $("#load_box #scenarios")

  get_data = ->
    if $('#flight_flightlesson_id option[value]:selected').text() == ''
      gi_container.text("You must select a lesson in the 'Flight Info' Tab")
      scenario_tell.text("")
      load_box.removeClass("is-fetching")
      lesson_tell.text "No Lesson Selected"

    else

      $.ajax
        url: "gradable_items_inputs?lesson=#{ f_lesson.val() }"
        
        beforeSend: ->
          load_box.addClass("is-fetching")
          lesson_tell.text("...loading gradable items")
          scenario_tell.text("...loading scenarios")

        success: (data) ->
          gi_container.html(data).find("#ajax_gradable_items_for_lesson_content")

        complete: ->
          lesson_tell.text("")
          scenario_tell.text("")
          load_box.removeClass("is-fetching")

        error: ->
          lesson_tell.text "ERROR"

  # get_data() # if this is un-commented...it runs over and over and over and over


  f_lesson.on "change", ->
    get_data()

gradable_items_tab.html.erb

<div id="gradable_items_container">
  // form inputs from tempate are loaded in here via AJAX
  
</div>

graded_items_inputs.html.erb

// this template is hit when the lesson_id input is changed
// this content is then loaded into the nested form into div#gradable_items_container

<div id="ajax_gradable_items_for_lesson_content">

	<% @subjects.each do |subject| %>
		<% unless lessons_gradable_items(subject, @lesson).blank? %>

		<%= subject.name %>
		
			<%= simple_fields_for @graded_items do |graded_item| %>
				
				<% lessons_gradable_items(subject, @lesson).each do |gradable_item| %>
						
					<%= gradable_item.name %>
							
					<%= graded_item.input :gradable_item_id, as: :hidden %>
					<%= graded_item.input :cfi_grade, collection: @grade_scales %>
              				<%= graded_item.input :pt_grade, collection: @grade_scales %>
						
						
				<% end %> <%# lessons_gradable_items %>
			<% end %> <%# fields_for %>
		<% end %> <%# unless not in subject %>
	<% end %> <%# GradableSubject %>
</div>