session,scope,rjs,option

http://railscasts.com/episodes/103-site-wide-announcements

<br /><!-- layouts/application.html.erb --><br /><% unless current_announcements.empty? %><br /><div id="announcement"><br /> <% for announcement in current_announcements %><br /> <p><%=h announcement.message %></p><br /> <% end %><br /> <p><%= link_to_remote "Hide this message", :url => "/javascripts/hide_announcement.js" %></p><br /></div><br /><% end %><br />

<br /># models/announcement.rb<br />def self.current_announcements(hide_time)<br /> with_scope :find => { :conditions => "starts_at <= now() AND ends_at >= now()" } do<br /> if hide_time.nil?<br /> find(:all)<br /> else<br /> find(:all, :conditions => ["updated_at > ? OR starts_at > ?", hide_time, hide_time])<br /> end<br /> end<br />end<br /><br /># application_helper.rb<br />def current_announcements<br /> @current_announcements ||= Announcement.current_announcements(session[:announcement_hide_time])<br />end<br /><br /># javascripts_controller.rb<br />def hide_announcement<br /> session[:announcement_hide_time] = Time.now<br />end<br /><br /># hide_announcement.js.rjs<br />page[:announcement].hide<br />