Bootstrap 4 Navbar在Rails应用程序中滚动时 Out中的Navbar vade

Question

我正在尝试弄清楚如何在Bootstrap 4中拥有顶级Navbar，然后当用户向下滚动时，在页面上向下滚动时，将NAVBAR 在前，我可以使用以下脚本显示Navbar来显示，但是，它不会立即逐渐淡出非常快速，尴尬。

<script>
$(document).scroll(function(e){
    var scrollTop = $(document).scrollTop();
    if(scrollTop > 200){
        $('.navbar').removeClass('static-top').addClass('fixed-top');
    } else {
        $('.navbar').removeClass('fixed-top').addClass('static-top');
    }
});
</script>
<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <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>
  <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>
    <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-primary my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav><!--./nav-->

我正在寻找这样的纳维尔效应，例如http://bootstraplovers.com/assan-v3.6/classic-template/html/index.html

Answer 1

$('.navbar').removeClass('static-top').addClass('fixed-top');

在调用.removeClass()之前，您需要致电.toggle()或其他类似的jQuery效果。请参阅文档

.toggle()会隐藏纳维托，所以也许您想在相关的stackoverflow部分（jQuery）中发布问题，请考虑如何构建此动画并搜索jQuery文档...