为什么引导程序不起作用？答案

【问题标题】：Why Bootstrap is not working?为什么引导程序不起作用？
【发布时间】：2017-03-21 01:34:20
【问题描述】：

我是 bootstrap 新手，所以无法正确显示导航

<!DOCTYPE html>
<html>
<head>
  <title>Title</title>
   <meta name="viewport" content="width=device-width, initial-scale=1">
    <link  href="./bower_components/bootstrap/dist/css/bootstrap.min.css" rel="stylesheet"/>
    <script src="./bower_components/jquery/dist/jquery.min.js"></script>
    <script src="./bower_components/bootstrap/dist/js/bootstrap.min.js"></script>
</head>
<body>
   <nav class="navbar navbar-toggleable-md navbar-light bg-faded">
    <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo02" aria-controls="navbarTogglerDemo02" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <a class="navbar-brand" href="#">Navbar</a>

    <div class="collapse navbar-collapse" id="navbarTogglerDemo02">
      <ul class="navbar-nav mr-auto mt-2 mt-md-0">
        <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">
          <a class="nav-link disabled" href="#">Disabled</a>
        </li>
      </ul>
      <form class="form-inline my-2 my-lg-0">
        <input class="form-control mr-sm-2" type="text" placeholder="Search">
        <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
      </form>
    </div>
  </nav>
    <button class="btn btn-success">Botón Verde</button>
</body>
</html>

我使用 bower 来安装 jquery 和 bootstrap。这是它的显示方式： https://ibb.co/bXhUdv

【问题讨论】：

你需要关闭你的<head>标签。
还需要一个文档类型。
你需要用开始页面你没有一个标签在头部呼出页面名称并且你没有关闭

标签： jquery css bootstrap-4

【解决方案1】：

根据评论编辑：

To install boostrap 4 alpha 6 through bower do:

bower install bootstrap#v4.0.0-alpha.6

原答案：

可能与凉亭有关，您确定您正在加载 bootstrap 4 alpha 6 而不是 bootstrap 3？ Fiddle 上的代码似乎很好，见下文：

尝试从 CDN 手动加载它，看看是否可以将问题隔离到 bower
还可以考虑在 </body> 结束标记之前加载各自订单上的所有 JS 文件。

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.3.7/js/tether.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js" integrity="sha384-vBWWzlZJ8ea9aCX4pEW3rVHjgjt7zpkNpZk+02D9phzyeVkE+jo0ieGizqPLForn" crossorigin="anonymous"></script>
<nav class="navbar navbar-toggleable-md navbar-light bg-faded">
  <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo02" aria-controls="navbarTogglerDemo02" aria-expanded="false" aria-label="Toggle navigation">
     <span class="navbar-toggler-icon"></span>
  </button>
  <a class="navbar-brand" href="#">Navbar</a>
  <div class="collapse navbar-collapse" id="navbarTogglerDemo02">
    <ul class="navbar-nav mr-auto mt-2 mt-md-0">
      <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">
        <a class="nav-link disabled" href="#">Disabled</a>
      </li>
    </ul>
    <form class="form-inline my-2 my-lg-0">
      <input class="form-control mr-sm-2" type="text" placeholder="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav>
<button class="btn btn-success">Botón Verde</button>

【讨论】：

我输入了“bower install bootstrap”我应该输入“bower install bootstrap #v4.0.0-alpha.6”来指定引导程序版本。非常感谢您的帮助（：
bower install bootstrap#v4.0.0-alpha.6 - 上面还添加了来自官方文档的参考 :)