Bare example of link_to_remote: clicking the "Update" link in the view will change the text in the update_me span to 'Updated text.'

some_random_view.html.erb

<span id="update_me">Some text that needs to be updated.</span>
<%=link_to_remote "Update", :url => "/update/something", :update => 'update_me' %>

update_controller.rb

# GET  /update/something
# POST /update/something
def something
  respond_to do |format|
    format.js { render :text => 'Updated text.' }
  end
end

#clicking the "Update" link in the view will change the text in the update_me span to 'Updated text.'