Question

因此，我目前正在W3Schools上学习CSS，并且试图创建一个包含下拉菜单的导航栏。我正在尝试重新创建此（顺便说一句，效果很好）：

<!DOCTYPE html>
<html>
<head>
<style>
ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333;
}

li {
  float: left;
}

li a {
  display: inline-block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

li a:hover, .dropdown:hover {
  background-color: red;
}

.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;
  text-decoration: none;
  display: block;
  text-align: left;
}

.dropdown-content a:hover {background-color: #f1f1f1;}

.dropdown:hover .dropdown-content {
  display: block;
}
</style>
</head>
<body>

<ul>
  <li><a href="#home">Home</a></li>
  <li><a href="#news">News</a></li>
  <li class="dropdown">
    <a href="#">Dropdown</a>
    <div class="dropdown-content">
      <a href="#">Link 1</a>
      <a href="#">Link 2</a>
      <a href="#">Link 3</a>
    </div>
  </li>
</ul>

<h3>Dropdown Menu inside a Navigation Bar</h3>
<p>Hover over the "Dropdown" link to see the dropdown menu.</p>

</body>
</html>

这是我的代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Dropdown Navigation Bar</title>
    <style>
        div.nrm {
            position: fixed;
            top: 0;
            left: 0;
        }

        body {
            background-color: #BCBF69;
            font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
            color: white;
        }

        ul {
            list-style-type: none;
            padding: 0;
            margin: 0;
            overflow: hidden;
            background-color: #212226;
            width: 100%;
        }

        li {
            float: left;
        }

        li a {
            display: inline-block;
            color: white;
            text-align: center;
            padding: 14px 15px;
            text-decoration: none;
        }

        .home {
            background-color: #D9A76A;
        }

        .home:hover {
            background-color: rgb(104, 94, 81);
        }

        li a:hover, .dropdown:hover {
            background-color: #494b50;
        }

        .dd-content {
            display: none;
            position: absolute;
            background-color: #D9A76A;
            min-width: 120px;
            z-index: 1;
        }

        .dd-content a {
            text-decoration: none;
            text-align: left;
            display: block;
        }

        .dd-content a:hover {
            background-color: rgb(230, 204, 172);
        }

        .dropdown:hover .dd-content {
            display: block;
        }
    </style>
</head>
<body>
    <div class="nrm">
        <ul>
            <li><a href="#home" class="home">Home</a></li>
            <li><a href="#explore">Explore</a></li>
            <li class="dropdown">
                <a href="#">Create</a></li>
                <div class="dd-content">
                    <a href="#">Media</a>
                    <a href="#">Games</a>
                    <a href="#">Other</a>
                </div>
        </ul>
    </div>
</body>
</html>

由于某种原因，当我将鼠标悬停在下拉菜单上时，它似乎没有任何作用。我真的可以帮忙。

Answer 1

dd内容必须位于<li>标记内，这就是为什么不起作用的原因。

    <div class="nrm">
    <ul>
        <li><a href="#home" class="home">Home</a></li>
        <li><a href="#explore">Explore</a></li>
        <li class="dropdown">
            <a href="#">Create</a>
            <div class="dd-content">
                <a href="#">Media</a>
                <a href="#">Games</a>
                <a href="#">Other</a>
            </div>
        </li>
    </ul>
</div>

Answer 2

第一件事是消除溢出：隐藏；从ul统治。您还需要将下拉列表放在li内。将父li设置为position：relative;

div.nrm {
  position: fixed;
  top: 0;
  left: 0;
}

body {
  background-color: #BCBF69;
  font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
  color: white;
}

ul {
  list-style-type: none;
  padding: 0;
  margin: 0;
  background-color: teal;
  width: 100%;
  display: flex;
}


li a {
  display: inline-block;
  color: white;
  text-align: center;
  padding: 14px 15px;
  text-decoration: none;
}

.home {
  background-color: #D9A76A;
}

.home:hover {
  background-color: rgb(104, 94, 81);
}

li a:hover,
.dropdown:hover {
  background-color: tomato;
}

.dropdown {
  position: relative;
}

.dd-content {
  display: none;
  position: absolute;
  right: 0;
  top: 100%;
  background-color: DarkOrchid;
  width: 100%;
  z-index: 1;
}

.dd-content a {
  text-decoration: none;
  text-align: left;
  display: block;
}

.dd-content a:hover {
  background-color: rgb(230, 204, 172);
}

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

<body>
  <div class="nrm">
    <ul>
      <li><a href="#home" class="home">Home</a></li>
      <li><a href="#explore">Explore</a></li>
      <li class="dropdown">
        <a href="#">Create</a>
          <div class="dd-content">
            <a href="#">Media</a>
            <a href="#">Games</a>
            <a href="#">Other</a>
          </div>
      </li>
    </ul>
  </div>
</body>

Answer 3

Css读取您的样式： .dropdown:hover .dd-content

嘿，当我将鼠标悬停在.dropdown:hover上时，我会看着我身边的一个目标{strong>

不存在，因为根据上述结构，您的目标是同级

所以在这种情况下，您必须说些别的话

.dd-content

现在css的读起来就像当我将鼠标悬停在.dropdown:hover + .dd-content上时，看看下一个兄弟姐妹称为.dropdown:hover

为什么导航栏下拉菜单不起作用？

3 个答案: