example.js.coffee

jQuery ->
  if $('.pagination').length
    $(window).scroll ->
      url = $('.pagination .next_page').attr('href')
      if url && $(window).scrollTop() > $(document).height() - $(window).height() - 50
        $('.pagination').text("Fetching more examples...")
        $.getScript(url)
    $(window).scroll()

examples_controller.rb

def index
  @exampless = Examples.order("our_column").page(params[:page]).per_page(10)
end

Gemfile

gem 'will_paginate'

index.html.erb

<div id="examples">
  <%= render @examples %>
</div>

<%= will_paginate @examples %>

index.js.erb

// Our ajax triggered code that corresponds with the rails controller action method.

$('#example').append('<%= j render(@exampless) %>');
<% if @exampless.next_page %>
  $('.pagination').replaceWith('<%= j will_paginate(@examples) %>');
<% else %>
  $('.pagination').remove();
<% end %>