如何修复白色背景。试图制作透明的导航栏答案

【问题标题】：How to fix white background. Trying to make transparent navbar如何修复白色背景。试图制作透明的导航栏
【发布时间】：2019-12-16 18:58:17
【问题描述】：

我想使用 bootstrap4 使用透明导航栏进行整页登陆。我想要一个导航栏，当你向下滚动时，它会粘在顶部。

当我使用“fixed-top”类时，它看起来不错，但向下滚动时却没有跟随。当我使用“sticky-top”时，它会使导航栏的背景变成白色。

<nav class="navbar navbar-expand-md navbar-dark bg-dark sticky-top">
    <div class="container-fluid">
         <a href="#" class="navbar-brand">Brand</a>
         <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarToggler-1" aria-controls="navbarToggler-1" aria-expanded="false" aria-label="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
         </button>

.bg-dark{
    background-color: transparent !important;
}

【问题讨论】：

标签： html css bootstrap-4 navbar

【解决方案1】：

我是这样设计的

html

<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>
</nav>

css

.navbar-fixed {
  top: 0;
  z-index: 100;
  position: fixed;
  width: 100%;
}
.navbar{
  background-color: transparent !important;
}

$(window).scroll(function () {
  console.log($(window).scrollTop())
  if ($(window).scrollTop() > 63) {
    $('.navbar').addClass('navbar-fixed');
  }
  if ($(window).scrollTop() < 64) {
    $('.navbar').removeClass('navbar-fixed');
  }
});

希望能帮到你

【讨论】：

【解决方案2】：

.navbar.bg-dark{
    background-color: transparent !important;
}

.navbar.navbar-dark .navbar-brand{
color: #000}

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.css" rel="stylesheet"/>
<nav class="navbar navbar-expand-md navbar-dark bg-dark sticky-top">
    <div class="container-fluid">
         <a href="#" class="navbar-brand">Brand</a>
         <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarToggler-1" aria-controls="navbarToggler-1" aria-expanded="false" aria-label="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
         </button>

【讨论】：

【解决方案3】：

您的导航栏从bg-dark获取背景颜色

只需从<nav class=""> 中删除类bg-dark

<nav class="navbar navbar-expand-md navbar-dark sticky-top">
    <div class="container-fluid">
         <a href="#" class="navbar-brand">Brand</a>
         <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarToggler-1" aria-controls="navbarToggler-1" aria-expanded="false" aria-label="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
         </button>
    </div>
</nav>

为什么？需要移除 bg-dark

因为bg-dark有这个属性
.bg-dark {
   background-color: #343a40 !important;
}

让我们来这里DEMO！

<body style="background-color: gray;">
  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
  <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>

  <nav class="navbar navbar-expand-md navbar-dark sticky-top">
    <div class="container-fluid">
      <a href="#" class="navbar-brand">Brand</a>
      <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarToggler-1" aria-controls="navbarToggler-1" aria-expanded="false" aria-label="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
         </button>
    </div>
    <div class="collapse navbar-collapse" id="navbarToggler-1">
      xxx
    </div>
  </nav>

  <img src="https://cdn.pixabay.com/photo/2016/02/19/11/19/computer-1209641_960_720.jpg">
</body>

【讨论】：

【解决方案4】：

你可以删除这个类（bg-dark），当它处于粘性状态时，它可以通过 js 完成，或者如果你只想使用 css，那么你必须像这样使用带有 bg-dark 的 body 类（body .bg- dark{background:none;} header .bg-dark{background:none;} ）如果你想添加它，你也可以添加重要的。

$(window).scroll(function() {    
    var scroll = $(window).scrollTop();

    if (scroll >= 300) {
        $(".navbar").addClass("sticky_nav");
        $(".navbar").removeClass("bg-dark");
    } else {
        $(".navbar").removeClass("sticky_nav");
        $(".navbar").addClass("bg-dark");
    }
});

.navbar.sticky_nav{
    position: fixed;
    top: 0;
    width: 100%;
    left: 0;
    z-index: 99;
}

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<nav class="navbar navbar-expand-md navbar-dark bg-dark sticky-top">
    <div class="container-fluid">
         <a href="#" class="navbar-brand">Brand</a>
         <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarToggler-1" aria-controls="navbarToggler-1" aria-expanded="false" aria-label="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
         </button>
         </div>
  </nav>
  <div style="height:200px; width:100%; background:#f00; display:block;"></div>
   <div style="height:300px; width:100%; background:#000; display:block;"></div>

【讨论】：