当我更改 max-height 和 overflow-y 时，具有搜索 input/icon 放置（绝对位置）的 Bootstrap 4 Navbar 不起作用

Question

我正在尝试在显示移动菜单时使带有嵌入式搜索图标的搜索输入在 Bootstrap 4 导航栏中工作。下面是我的 Boostrap 3 版本，它运行起来非常简单......

由于应用程序的性质，我有一个很长的 'mobile' 菜单，所以我想对导航栏折叠应用最大高度和溢出-y，这样它就不会覆盖整个屏幕。

但是，当我在 Boostrap 4 中应用这些样式时，我的搜索图标不会保留 'inside' 输入：

我应用于搜索输入的样式是：

<div class="has-search">
    <span class="fa fa-search form-control-feedback execute-quick-search"></span>
    <input type="text" class="form-control quick-search" placeholder="Quick Search">
</div>

.has-search .form-control {
  padding-right: 2.375rem;
}

.has-search .form-control-feedback {
  position: absolute;
  z-index: 2;
  display: block;
  width: 2.375rem;
  height: 2.375rem;
  line-height: 2.375rem;
  text-align: center;
  pointer-events: auto;
  cursor: pointer;
  right: 1.1875rem;
}

如果我将 max-height/overflow-y 样式应用到整个 .navbar 元素，我可以使搜索图标保留在输入框内。但这不是我想要的外观，更糟糕的是，它允许移动 togglerButton 滚出屏幕。我做了一个重现错误的 fiddle。

Fiddle

Answer 1

将 position: relative 添加到 has-search。也仅在 移动视图 .

中将 max-height 等应用于 navbar-collapse

参见下面的演示：

.has-search { /* ADDED */
  position: relative;
}

.has-search .form-control {
  padding-right: 2.375rem;
}

.has-search .form-control-feedback {
  position: absolute;
  z-index: 2;
  display: block;
  width: 2.375rem;
  height: 2.375rem;
  line-height: 2.375rem;
  text-align: center;
  pointer-events: auto;
  cursor: pointer;
  right: 1.1875rem;
}
@media (max-width: 991px) { /* ADDED */
  .navbar-collapse {
    max-height: 150px;
    overflow-y: auto;
  }
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css" />
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.1/css/all.css" />
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js"></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="#" tabindex="-1" aria-disabled="true">Disabled</a>
      </li>
    </ul>
    <div class="has-search">
      <span class="fa fa-search form-control-feedback execute-quick-search"></span>
      <input type="text" class="form-control quick-search" placeholder="Quick Search">
    </div>
  </div>
</nav>
<h1>Hello, world!</h1>

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