javascript - 下拉菜单没有反应

Question

我正在尝试根据屏幕尺寸使我的导航栏响应。目前一切正常，除非屏幕太小以至于显示“汉堡包”栏，按钮下的所有链接都不会显示。此外，当单击汉堡包栏时，并非所有链接都垂直显示，也并非所有服务下的链接都显示。

我已经尝试更改 dropdown.content 的 css，但到目前为止没有任何效果。

.navbar {
  overflow: hidden;
  background-color: #333;
  font-family: Arial, Helvetica, sans-serif;
}

.navbar a {
  float: left;
  font-size: 16px;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

.dropdown {
  float: left;
  overflow: hidden;
}

.dropdown .dropbtn {
  font-size: 16px;
  border: none;
  outline: none;
  color: white;
  padding: 14px 16px;
  background-color: inherit;
  font-family: inherit;
  margin: 0;
}

.navbar a:hover,
.dropdown:hover .dropbtn {
  background-color: #008CBA;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
  z-index: 1;
}

.dropdown-content a {
  float: none;
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  text-align: left;
}

.dropdown-content a:hover {
  background-color: #ddd;
}

.dropdown:hover .dropdown-content {
  display: block;
}

.navbar .icon {
  display: none;
}

@media screen and (max-width: 600px) {
  .navbar a:not(:first-child) {
    display: none;
  }
  .navbar a.icon {
    float: right;
    display: block;
  }
}

@media screen and (max-width: 600px) {
  .navbar.responsive {
    position: relative;
  }
  .navbar.responsive .icon {
    position: absolute;
    right: 0;
    top: 0;
  }
  .navbar.responsive a {
    float: none;
    display: block;
    text-align: left;
  }
}

<div class="navbar" id="myNavBar">
  <a href="#home">Home</a>
  <div class="dropdown">
    <button class="dropbtn">Services 
    				<i class="fa fa-caret-down"></i>
    			</button>
    <div class="dropdown-content">
      <a href="#">Red or Black Tarmac Drives and Paths</a>
      <a href="#">Fencing and Gates</a>
      <a href="#">Shingle and Coloured Gravels</a>
      <a href="#">Drainage Work</a>
      <a href="#">Patios and Crazy Paving</a>
      <a href="#">Block Paved Driveways and Paths</a>
      <a href="#">Turfing and Artificial Grass</a>
      <a href="#">Brick and Purbeck Stone Walls</a>
      <a href="#">Decking and Rockeries</a>
    </div>
    <!-- /dropdown-content -->
  </div>
  <!-- /dropdown -->
  <a href="#home">Gallary</a>
  <a href="#home">Before and After</a>
  <a href="#home">Testimonials</a>
  <a href="#home">Contact Us</a>
  <a href="javascript:void(0);" class="icon" onclick="myFunction()">
    <i class="fa fa-bars"></i>
  </a>
</div>
<!-- /navbar -->

<div style="padding-left:16px">
  <h2>Responsive Topnav Example</h2>
  <p>Resize the browser window to see how it works.</p>
</div>

我已经把它放在一个 jsfiddle 中，下面是链接

https://jsfiddle.net/knrvmdu5/

如有任何帮助，我们将不胜感激

Answer 1

我删除了你所有的 float 规则并用 flexbox 替换它们. float 很难管理，我可以告诉您必须将 overflow: hidden 添加到您的 .navbar 以确保它会显示 float 元素，这就是原因之一您的服务菜单被切断了。我还在链接中添加了独特的类，这样您就可以更轻松地定位它们。您的 .navbar a:not(first-child) 规则导致您的嵌套服务菜单链接不显示:

/* ========== NAVIGATION BAR ========== */

.navbar {
  background-color: #333;
  font-family: Arial, Helvetica, sans-serif;
  display: flex;
  justify-content: space-between;
}

.navbar a {
  font-size: 16px;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

.dropdown {
  overflow: hidden;
  display: inline;
}

.dropdown .dropbtn {
  font-size: 16px;
  border: none;
  outline: none;
  color: white;
  padding: 14px 16px;
  background-color: inherit;
  font-family: inherit;
  margin: 0;
}

.navbar a:hover,
.dropdown:hover .dropbtn {
  background-color: #008CBA;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
  z-index: 1;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  text-align: left;
}

.dropdown-content a:hover {
  background-color: #ddd;
}

.dropdown:hover .dropdown-content {
  display: block;
}

.navbar .icon {
  display: none;
}

@media screen and (max-width: 685px) {
  .nav-link:not(:first-child) {
    display: none;
  }
  .navbar a.icon {
    display: block;
  }
}

@media screen and (max-width: 685px) {
  .navbar.responsive {
    position: relative;
  }
  .navbar.responsive .icon {
    position: absolute;
    right: 0;
    top: 0;
  }
  .navbar.responsive a {
    display: block;
    text-align: left;
  }
  .dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
    z-index: 1;
  }
  .dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
    text-align: left;
  }
  .dropdown-content a:hover {
    background-color: #ddd;
  }
  .dropdown:hover .dropdown-content {
    display: block;
  }
}

<!DOCTYPE html>
<html>

  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">

  </head>

  <body>

    <div class="navbar" id="myNavBar">
      <div class="links">
        <a href="#home" class="nav-link">Home</a>
        <div class="dropdown">
          <button class="dropbtn">Services 
            <i class="fa fa-caret-down"></i>
          </button>
          <div class="dropdown-content">
            <a href="#">Red or Black Tarmac Drives and Paths</a>
            <a href="#">Fencing and Gates</a>
            <a href="#">Shingle and Coloured Gravels</a>
            <a href="#">Drainage Work</a>
            <a href="#">Patios and Crazy Paving</a>
            <a href="#">Block Paved Driveways and Paths</a>
            <a href="#">Turfing and Artificial Grass</a>
            <a href="#">Brick and Purbeck Stone Walls</a>
            <a href="#">Decking and Rockeries</a>
          </div>
          <!-- /dropdown-content -->
        </div>
        <!-- /dropdown -->
        <a href="#home" class="nav-link">Gallery</a>
        <a href="#home" class="nav-link">Before and After</a>
        <a href="#home" class="nav-link">Testimonials</a>
      <a href="#home" class="nav-link">Contact Us</a>
      </div>
      <a href="javascript:void(0);" class="icon" onclick="myFunction()">
        <i class="fa fa-bars"></i>
      </a>
    </div>
    <!-- /navbar -->

    <div style="padding-left:16px">
      <h2>Responsive Topnav Example</h2>
      <p>Resize the browser window to see how it works.</p>
    </div>

    <script>
      function myFunction() {
        var x = document.getElementById("myNavBar");
        if (x.className === "navbar") {
          x.className += " responsive";
        } else {
          x.className = "navbar";
        }
      }

    </script>

  </body>

</html>