9-1 一般導覽列

1. https://github.com/tawan158/gallery/blob/master/20180626.html
   原始碼

   
       <!-- 上方選單 -->
       <div class="header" id="header">
         <nav class="navbar navbar-expand-lg navbar-light bg-light">          
           <div class="container-fluid">
             <!-- 品牌 -->
             <a class="navbar-brand" href="#">Navbar</a>
             <!-- 切換按鈕 -->
             <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
               <span class="navbar-toggler-icon"></span>
             </button>
             <!-- 下拉選單 -->
             <div class="collapse navbar-collapse" id="navbarSupportedContent">
               <ul class="navbar-nav mr-auto">
                 <li class="nav-item active">
                   <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
                 </li>
                 <li class="nav-item">
                   <a class="nav-link" href="#">Link</a>
                 </li>
                 <li class="nav-item dropdown">
                   <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                     Dropdown
                   </a>
                   <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                     <a class="dropdown-item" href="#">Action</a>
                     <a class="dropdown-item" href="#">Another action</a>
                     <div class="dropdown-divider"></div>
                     <a class="dropdown-item" href="#">Something else here</a>
                   </div>
                 </li>
                 <li class="nav-item">
                   <a class="nav-link disabled" href="#">Disabled</a>
                 </li>
               </ul>
               <!-- 搜尋 -->
               <form class="form-inline my-2 my-lg-0">
                 <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
                 <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
               </form>
             </div>
           </div>
         </nav>
       </div>    

    

2.