| Module | ActionView::Helpers::CacheHelper | 
| In: | lib/action_view/helpers/cache_helper.rb | 
This helper to exposes a method for caching of view fragments. See ActionController::Caching::Fragments for usage instructions.
A method for caching fragments of a view rather than an entire action or page. This technique is useful caching pieces like menus, lists of news topics, static HTML fragments, and so on. This method takes a block that contains the content you wish to cache. See ActionController::Caching::Fragments for more information.
If you wanted to cache a navigation menu, you could do the following.
  <% cache do %>
    <%= render :partial => "menu" %>
  <% end %>
You can also cache static content…
  <% cache do %>
     <p>Hello users!  Welcome to our website!</p>
  <% end %>
…and static content mixed with RHTML content.
   <% cache do %>
     Topics:
     <%= render :partial => "topics", :collection => @topic_list %>
     <i>Topics listed alphabetically</i>
   <% end %>