1、导航栏

  1. <nav class="navbar navbar-expand-lg bg-light"><!-- 响应式：navbar-expand-lg可以聚集到左边 -->
  2.     <a href="#" class="navbar-brand">
  3.         <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  4.             class="align-top"> Bootstrap<!-- align-top：居中对齐 -->
  5.     </a>
  6.     <ul class="navbar-nav">
  7.         <li class="nav-item"><a href="#" class="nav-link">入门</a></li>
  8.         <li class="nav-item"><a href="#" class="nav-link">布局</a></li>
  9.         <li class="nav-item"><a href="#" class="nav-link">内容</a></li>
  10.         <li class="nav-item dropdown">
  11.             <a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown">城市</a>
  12.             <div class="dropdown-menu">
  13.                 <a href="#" class="dropdown-item">北京</a>
  14.                 <a href="#" class="dropdown-item">上海</a>
  15.                 <a href="#" class="dropdown-item">广州</a>
  16.                 <div class="dropdown-divider"></div>
  17.                 <a href="#" class="dropdown-item">深圳</a>
  18.             </div>
  19.         </li>
  20.     </ul>
  21.     <!-- <div class="navbar-nav">
  22.         <a href="#" class="nav-item nav-link">入门</a>
  23.         <a href="#" class="nav-item nav-link">布局</a>
  24.         <a href="#" class="nav-item nav-link">内容</a>
  25.         <a href="#" class="nav-item nav-link">组件</a>
  26.     </div> -->
  27. </nav>

2、表单

  1. <nav class="navbar bg-light mt-5">
  2.     <a href="#" class="navbar-brand">
  3.         <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  4.             class="align-top"> Bootstrap
  5.     </a>
  6.     <form action="#" class="form-inline"><!-- form-inline -->
  7.         <!-- <input type="search" class="form-control mr-sm-2" placeholder="Search">
  8.         <button type="submit" class="btn btn-outline-success mt-2 mt-sm-0">Search</button> -->
  9.         <!-- 输入框组 -->
  10.         <div class="input-group">
  11.             <div class="input-group-prepend">
  12.                 <span class="input-group-text">@</span>
  13.             </div>
  14.             <input type="search" class="form-control mr-sm-2" placeholder="Search">
  15.         </div>
  16.         <button type="submit" class="btn btn-outline-success mt-2 mt-sm-0">Search</button><!-- mt-2 mt-sm-0：超过sm的为0，小于mt的top为2 -->
  17.     </form>
  18. </nav>

3、添加文本：navbar-text

  1. <nav class="navbar navbar-expand-lg bg-light mt-5">
  2.     <a href="#" class="navbar-brand">
  3.         <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  4.             class="align-top"> Bootstrap
  5.     </a>
  6.     <ul class="navbar-nav mr-auto"><!-- mr-auto：让文本到最右边 -->
  7.         <li class="nav-item"><a href="#" class="nav-link">入门</a></li>
  8.         <li class="nav-item"><a href="#" class="nav-link">布局</a></li>
  9.         <li class="nav-item"><a href="#" class="nav-link">内容</a></li>
  10.     </ul>
  11.     <span class="navbar-text">这是导航当中的文本</span>
  12. </nav>

4、颜色

  1. <nav class="navbar navbar-expand-lg bg-dark navbar-dark mt-5">
  2.     <!-- 
  3.         bg-dark：背景颜色
  4.         navbar-dark：字体颜色 dark为浅色，light为深色
  5.      -->
  6.     <a href="#" class="navbar-brand">
  7.         <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  8.             class="align-top"> Bootstrap
  9.     </a>
  10.     <ul class="navbar-nav mr-auto">
  11.         <li class="nav-item"><a href="#" class="nav-link">入门</a></li>
  12.         <li class="nav-item"><a href="#" class="nav-link">布局</a></li>
  13.         <li class="nav-item"><a href="#" class="nav-link">内容</a></li>
  14.     </ul>
  15.     <form action="#" class="form-inline">
  16.         <input type="search" class="form-control mr-sm-2" placeholder="Search">
  17.         <button type="submit" class="btn btn-outline-success mt-2 mt-sm-0">Search</button>
  18.     </form>
  19. </nav>

5、居中容器：仅有中间一段

  1. <div class="container">
  2.     <!-- 
  3.         container：放在nav外面，背景仅占中间
  4.         放在nav里面，仅字占中间
  5.      -->
  6.     <nav class="navbar navbar-expand-lg bg-dark navbar-dark mt-5">
  7.         <a href="#" class="navbar-brand">
  8.             <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  9.                 class="align-top"> Bootstrap
  10.         </a>
  11.         <ul class="navbar-nav mr-auto">
  12.             <li class="nav-item"><a href="#" class="nav-link">入门</a></li>
  13.             <li class="nav-item"><a href="#" class="nav-link">布局</a></li>
  14.             <li class="nav-item"><a href="#" class="nav-link">内容</a></li>
  15.         </ul>
  16.         <form action="#" class="form-inline">
  17.             <input type="search" class="form-control mr-sm-2" placeholder="Search">
  18.             <button type="submit" class="btn btn-outline-success mt-2 mt-sm-0">Search</button>
  19.         </form>
  20.     </nav>
  21. </div>

6、定位：fixed-top fixed-bottom sticky-top

  1. <!-- <nav class="navbar navbar-light bg-light fixed-top">
  2.         <a href="#" class="navbar-brand">因定在顶部</a>
  3.     </nav> -->
  4. <nav class="navbar navbar-light bg-light fixed-bottom">
  5.     <a href="#" class="navbar-brand">因定在底部</a>
  6. </nav>
  7. <nav class="navbar navbar-light bg-light sticky-top">
  8.     <a href="#" class="navbar-brand">粘性定位在浏览器的顶部</a>
  9. </nav>

7、响应式

  1. <!-- 响应式 -->
  2. <nav class="navbar navbar-expand-md bg-success navbar-dark mt-5"><!--  navbar-expand-md：主管隐藏尺寸 -->
  3.     <button class="navbar-toggler" data-toggle="collapse" data-target="#navbar"><!-- collapse：折叠面板；注意data-的属性 -->
  4.         <span class="navbar-toggler-icon"></span><!-- navbar-toggler-icon：三条杠 -->
  5.     </button>
  6.     <div class="collapse navbar-collapse" id="navbar"><!-- navbar-collapse：根据navbar-expand-md来选择是否弹性盒模型 -->
  7.         <a href="#" class="navbar-brand">
  8.             <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  9.                 class="align-top"> Bootstrap
  10.         </a>
  11.         <ul class="navbar-nav mr-auto">
  12.             <li class="nav-item"><a href="#" class="nav-link">入门</a></li>
  13.             <li class="nav-item"><a href="#" class="nav-link">布局</a></li>
  14.             <li class="nav-item"><a href="#" class="nav-link">内容</a></li>
  15.         </ul>
  16.         <form action="#" class="form-inline">
  17.             <input type="search" class="form-control mr-sm-2" placeholder="Search">
  18.             <button type="submit" class="btn btn-outline-light mt-2 mt-sm-0">Search</button>
  19.         </form>
  20.     </div>
  21. </nav>
  22. <!-- 左侧是logo，右侧是按钮 -->
  23. <nav class="navbar navbar-expand-md bg-success navbar-dark mt-5">
  24.     <a href="#" class="navbar-brand">
  25.         <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  26.             class="align-top"> Bootstrap
  27.     </a>
  28.     <button class="navbar-toggler" data-toggle="collapse" data-target="#navbar1">
  29.         <span class="navbar-toggler-icon"></span>
  30.     </button>
  31.     <div class="collapse navbar-collapse" id="navbar1">
  32.         <ul class="navbar-nav mr-auto">
  33.             <li class="nav-item"><a href="#" class="nav-link">入门</a></li>
  34.             <li class="nav-item"><a href="#" class="nav-link">布局</a></li>
  35.             <li class="nav-item"><a href="#" class="nav-link">内容</a></li>
  36.         </ul>
  37.         <form action="#" class="form-inline">
  38.             <input type="search" class="form-control mr-sm-2" placeholder="Search">
  39.             <button type="submit" class="btn btn-outline-light mt-2 mt-sm-0">Search</button>
  40.         </form>
  41.     </div>
  42. </nav>
  43. <!-- 左侧是按钮，右侧是logo -->
  44. <nav class="navbar navbar-expand-md bg-success navbar-dark mt-5">
  45.     <button class="navbar-toggler" data-toggle="collapse" data-target="#navbar2">
  46.         <span class="navbar-toggler-icon"></span>
  47.     </button>
  48.     <a href="#" class="navbar-brand">
  49.         <img src="http://getbootstrap.com/docs/4.1/assets/brand/bootstrap-solid.svg" alt="" width="30"
  50.             class="align-top"> Bootstrap
  51.     </a>
  52.     <div class="collapse navbar-collapse" id="navbar2">
  53.         <ul class="navbar-nav mr-auto">
  54.             <li class="nav-item"><a href="#" class="nav-link">入门</a></li>
  55.             <li class="nav-item"><a href="#" class="nav-link">布局</a></li>
  56.             <li class="nav-item"><a href="#" class="nav-link">内容</a></li>
  57.         </ul>
  58.         <form action="#" class="form-inline">
  59.             <input type="search" class="form-control mr-sm-2" placeholder="Search">
  60.             <button type="submit" class="btn btn-outline-light mt-2 mt-sm-0">Search</button>
  61.         </form>
  62.     </div>
  63. </nav>
  64. <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
  65.     integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
  66.     crossorigin="anonymous"></script>
  67. <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"
  68.     integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1"
  69.     crossorigin="anonymous"></script>
  70. <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"
  71.     integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM"
  72.     crossorigin="anonymous"></script>