1. 下拉菜单通常使用在鼠标过程中，当鼠标悬停是出现一个下拉的菜单。
2. 使用任何元素打开下拉菜单内容，例如<span>或<button>元素
3. 使用容器元素<如div>创建下拉内容，并在其中添加任何内容。
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常见下拉菜单
<!DOCTYPE html>
<html>
<head>
<style>
.dropbtn {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropdown {
position: relative;
display: inline-block;
}
.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;
}
.dropdown-content a:hover {background-color: #f1f1f1}
.dropdown:hover .dropdown-content {
display: block;
}
.dropdown:hover .dropbtn {
background-color: #3e8e41;
}
</style>
</head>
<body>
<h1>下拉菜单</h1>
<p>请把鼠标移到按钮上，以打开下拉菜单。</p>
<div class="dropdown">
<button class="dropbtn">Dropdown</button>
<div class="dropdown-content">
<a href="#">Link 1</a>
<a href="#">Link 2</a>
<a href="#">Link 3</a>
</div>
</div>
<p><b>Note:</b>我们的测试链接用了 href="#"。真实的网站会用 URL。</p>
</body>
</html>
-
下拉式图像
1. 鼠标悬停后，将图片放大。
<!DOCTYPE html>
<html>
<head>
<style>
.dropdown {
position: relative;
display: inline-block;
}
.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:hover .dropdown-content {
display: block;
}
.desc {
padding: 15px;
text-align: center;
}
</style>
</head>
<body>
<h1>下拉图片</h1>
<p>请把鼠标移动到图像上，以打开下拉内容。</p>
<div class="dropdown">
<img src="/i/photo/coffee.jpg" alt="Coffee" width="100">
<div class="dropdown-content">
<img src="/i/photo/coffee.jpg" alt="Coffee" width="300" height="200">
<div class="desc">Coffee</div>
</div>
</div>
</body>
</html>
-
下拉式导航栏
<!DOCTYPE html>
<html>
<head>
<style>
ul {
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
background-color: #333;
}
li {
float: left;
}
li a, .dropbtn {
display: inline-block;
color: white;
text-align: center;
padding: 14px 16px;
text-decoration: none;
}
li a:hover, .dropdown:hover .dropbtn {
background-color: red;
}
li.dropdown {
display: inline-block;
}
.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: #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="javascript:void(0)" class="dropbtn">Dropdown</a>
<div class="dropdown-content">
<a href="#">Link 1</a>
<a href="#">Link 2</a>
<a href="#">Link 3</a>
</div>
</li>
</ul>
<h1>导航栏内的下拉菜单</h1>
<p>请悬停到 "Dropdown" 链接上，以查看下拉菜单。</p>
</body>
</html>
标签：dropdown,color,下拉菜单,content,background,display,CSS From： https://www.cnblogs.com/xinbing/p/16788821.html