我正在使用 CodePen 开发一个项目，并使用 bootstrap 来制作导航栏。但由于某种原因，它是垂直显示而不是水平显示。即使我从W3学校 https://www.w3schools.com/bootstrap/bootstrap_navbar.asp示例和引导网站 https://getbootstrap.com/components/#navbar-default。我不知道还能做什么。请帮忙。

这是 W3Schools 示例代码：

    <nav class="navbar navbar-default">
      <div class="container-fluid">
        <div class="navbar-header">
          <a class="navbar-brand" href="#">WebSiteName</a>
        </div>
        <ul class="nav navbar-nav">
          <li class="active"><a href="#">Home</a></li>
          <li><a href="#">Page 1</a></li>
          <li><a href="#">Page 2</a></li>
          <li><a href="#">Page 3</a></li>
        </ul>
      </div>

这是 Bootstrap 网站的示例代码：

    <nav class="navbar navbar-default">
      <div class="container-fluid">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
  <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
    <span class="sr-only">Toggle navigation</span>
    <span class="icon-bar"></span>
    <span class="icon-bar"></span>
    <span class="icon-bar"></span>
  </button>
  <a class="navbar-brand" href="#">Brand</a>
</div>

<!-- Collect the nav links, forms, and other content for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
  <ul class="nav navbar-nav">
    <li class="active"><a href="#">Link <span class="sr-only">(current)</span></a></li>
    <li><a href="#">Link</a></li>
    <li class="dropdown">
      <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Dropdown <span class="caret"></span></a>
      <ul class="dropdown-menu">
        <li><a href="#">Action</a></li>
        <li><a href="#">Another action</a></li>
        <li><a href="#">Something else here</a></li>
        <li role="separator" class="divider"></li>
        <li><a href="#">Separated link</a></li>
        <li role="separator" class="divider"></li>
        <li><a href="#">One more separated link</a></li>
      </ul>
    </li>
  </ul>
  <form class="navbar-form navbar-left">
    <div class="form-group">
      <input type="text" class="form-control" placeholder="Search">
    </div>
    <button type="submit" class="btn btn-default">Submit</button>
  </form>
  <ul class="nav navbar-nav navbar-right">
    <li><a href="#">Link</a></li>
    <li class="dropdown">
      <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Dropdown <span class="caret"></span></a>
      <ul class="dropdown-menu">
        <li><a href="#">Action</a></li>
        <li><a href="#">Another action</a></li>
        <li><a href="#">Something else here</a></li>
        <li role="separator" class="divider"></li>
        <li><a href="#">Separated link</a></li>
      </ul>
    </li>
  </ul>
</div><!-- /.navbar-collapse -->

两者都不起作用。是的，我已经三次检查了我的<link> and <script> tags.

Edit: 这是我的 CodePen https://codepen.io/RyanED/pen/PjBdWd/

首先，就像在评论中一样，您正在使用 bootstrap 3 标记，并且链接到 bootstrap 3 和 4，删除 bootstrap 4 css。然后你需要有类的divcollapse navbar-collapse所以只需将其添加到 id 为nav就像下面这样：

<nav class="navbar navbar-inverse">
  <div class="container-fluid">

    <div class="navbar-header">
      <a class="navbar-brand" href="#about">
        <span style="font-family: 'Source Code Pro', Monospace; color:green"><i class="fa fa-code"></i>Ryan</span></a>
    </div>
    <div class="collapse navbar-collapse"  id="nav">
    <ul class="nav navbar-nav">
      <li><a href="#about">About</a></li>
      <li><a href="#portfolio">Portfolio</a></li>
      <li><a href="#contact">Contact</a></li>
    </ul>
    </div>
  </div>
</nav> 

您可能还想将折叠按钮添加到导航栏标题中，否则您的链接将不会显示在移动设备宽度上，因此它看起来像：

<nav class="navbar navbar-inverse">
  <div class="container-fluid">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#nav" aria-expanded="false">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#about">
        <span style="font-family: 'Source Code Pro', Monospace; color:green"><i class="fa fa-code"></i>Ryan</span>
      </a>
    </div>
    <div class="collapse navbar-collapse"  id="nav">
    <ul class="nav navbar-nav">
      <li><a href="#about">About</a></li>
      <li><a href="#portfolio">Portfolio</a></li>
      <li><a href="#contact">Contact</a></li>
    </ul>
    </div>
  </div>
</nav>