bootstrap layout設計

1.navbar

  <nav id="top_menu_1"class="navbar navbar-default navbar-static-top" role="navigation"     style="top:125px;background:white;">
 
   固定頂端:  navbar-fixed-top

   不固定:  navbar-static-top



2.各物件範例:
http://v4-alpha.getbootstrap.com/components/popovers/