如何让引导导航栏与用户一起滚动？

Question

自从我上次编写任何程序以来已经有一段时间了。我想复制导航栏here使用的效果。然而，我设法得出的最接近实际代码的是：

$('body').on('scroll', function() {
    $('.navbar').css("bottom", $('.navbar').outerHeight(true));
});

如何解决此问题以复制上面链接中的效果？

Answer 1

这很容易。只需在此处查看此示例：

https://getbootstrap.com/docs/4.0/examples/navbar-top-fixed/

只需将 CSS 类 fixed-top 放入您的导航元素，如示例中所示：

<nav class="navbar navbar-expand-md navbar-dark fixed-top bg-dark">
  <a class="navbar-brand" href="#">Fixed navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarCollapse">
    <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">
        <a class="nav-link disabled" href="#">Disabled</a>
      </li>
    </ul>
    <form class="form-inline mt-2 mt-md-0">
      <input class="form-control mr-sm-2" type="text" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav>

如果您希望导航栏在滚动后立即粘在浏览器边缘，请使用 CSS 类 sticky-top，例如

    <nav class="navbar sticky-top navbar-light bg-light"><a class="navbar-brand" href="#">Sticky top</a></nav>

见https://getbootstrap.com/docs/4.0/components/navbar/#placement