def horizontal(*args, &block)
      if navbar = Bh::Stack.find(Bh::Navbar)
        horizontal = Bh::Base.new self, *args, &block
        horizontal.append_class! :'collapse navbar-collapse'
        horizontal.merge! id: navbar.id
        horizontal.render_tag :div
      end
    end
def horizontal(*args, &block)
      if navbar = Bh::Stack.find(Bh::Navbar)
        horizontal = Bh::Base.new self, *args, &block
        horizontal.append_class! :'collapse navbar-collapse'
        horizontal.merge! id: navbar.id
        horizontal.render_tag :div
      end
    end
Displays the collapsable portion of a Bootstrap-styled navbar.
 @see http://getbootstrap.com/components/#navbar
 @return [String] the HTML to display the collapsable portion of a
   Bootstrap-styled navbar.
 @overload horizontal(content, options = {})
   @param [#to_s] content the collapsable content to display in the navbar.
   @param [Hash] options the options to pass to the wrapping `<div>`.
     Note that the `:id` option is ignored since the id must generated
     by the navbar in order to match with the target of the toggle button.
 @overload horizontal(options = {}, &block)
   @param [Hash] options the options to pass to the wrapping `<div>`.
   @yieldreturn [#to_s] the collapsable content to display in the navbar.
 @example Display a navbar with two collapsable links.
   navbar do
     horizontal do
       nav do
         link_to 'Home', '/'
         link_to 'Profile', '/profile'
       end
     end
   end