CSS Drop-down Menu
Use CSS to create an effect that displays a drop-down menu when the mouse is moved up.
Basic drop-down menu
When the mouse moves over the specified element, a drop-down menu will appear.
Example
<!DOCTYPE html>
<html>
<head>
<title> PHP中文网（php.cn）</title>
<meta charset="utf-8">
<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 rgb(83, 251, 185);
padding: 12px 16px;
}
.dropdown:hover .dropdown-content {
display: block;
}
</style>
</head>
<body>
<div class="dropdown">
<span>鼠标移动到我这！</span>
<div class="dropdown-content">
<p> PHP中文网（php.cn）</p>
<p>www.php.cn</p>
</div>
</div>
</body>
</html>Run the program and try it
Example analysis
HTML part:
We can use any HTM element to open the drop-down menu, such as: <span>, or a <button> element.
Use a container element (such as <div>) to create the content of the drop-down menu and place it wherever you want.
Use <div> elements to wrap these elements, and use CSS to style the dropdown content.
CSS part: The
.dropdown class uses position:relative, which will set the content of the drop-down menu to be placed in the lower right corner of the drop-down button (using position:absolute). The
.dropdown-content class is the actual drop-down menu. It is hidden by default and will be displayed after the mouse moves to the specified element. Note that the min-width value is set to 160px. You can modify it as you like. Note: If you want to set the drop-down content to be consistent with the width of the drop-down button, you can set width to 100% (the overflow:auto setting can scroll on small screens).
We use the box-shadow attribute to make the drop-down menu look like a "card".
:hover selector is used to display the drop-down menu when the user moves the mouse over the drop-down button.
Drop-down menu
Create a drop-down menu and allow users to select an item in the list. We added a link to the drop-down list and set the style:
<!DOCTYPE html>
<html>
<head>
<title>PHP中文网(php.cn)</title>
<meta charset="utf-8">
<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);
}
.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>
<h2>下拉菜单</h2>
<p>鼠标移动到按钮上打开下拉菜单。</p>
<div class="dropdown">
<button class="dropbtn">下拉菜单</button>
<div class="dropdown-content">
<a href="http://www.php.cn">PHP中文网 1</a>
<a href="http://www.php.cn">PHP中文网 2</a>
<a href="http://www.php.cn">PHP中文网 </a>
</div>
</div>
</body>
</html>Run the program to try it
Alignment of drop-down content
left float:left;
right float:right;
##Example
<!DOCTYPE html>
<html>
<head>
<title>PHP中文网(php.cn)</title>
<meta charset="utf-8">
<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;
right: 0;
background-color: #f9f9f9;
min-width: 160px;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
}
.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>
<h2>下拉内容的对齐方式</h2>
<p>left 和 right 属性指定了下拉内容是从左到右或从右到左。</p>
<div class="dropdown" style="float:left;">
<button class="dropbtn">左</button>
<div class="dropdown-content" style="left:0;">
<a href="#">PHP中文网 1</a>
<a href="#">PHP中文网 2</a>
<a href="#">PHP中文网 3</a>
</div>
</div>
<div class="dropdown" style="float:right;">
<button class="dropbtn">右</button>
<div class="dropdown-content">
<a href="#">PHP中文网 1</a>
<a href="#">PHP中文网 2</a>
<a href="#">PHP中文网 3</a>
</div>
</div>
</body>
</html>Run the program and try it
More examples
This example demonstrates how to add a drop-down menu to the navigation bar.
<!DOCTYPE html>
<html>
<head>
<title>PHP中文网(php.cn)</title>
<meta charset="utf-8">
<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: #111;
}
.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);
}
.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;
}
</style>
</head>
<body>
<ul>
<li><a class="active" href="">主页</a></li>
<li><a href="">新闻</a></li>
<div class="dropdown">
<a href="#" class="dropbtn">下拉菜单</a>
<div class="dropdown-content">
<a href="#">链接 1</a>
<a href="#">链接 2</a>
<a href="#">链接 3</a>
</div>
</div>
</ul>
<p>鼠标移动到 "下拉菜单" 链接先显示下拉菜单。</p>
</body>
</html>Run the program and try it
Example
How to add pictures in the drop-down menu.
<!DOCTYPE html>
<html>
<head>
<title>PHP中文网（php.cn）</title>
<meta charset="utf-8">
<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);
}
.dropdown:hover .dropdown-content {
display: block;
}
.desc {
padding: 15px;
text-align: center;
}
</style>
</head>
<body>
<p>移动鼠标到图片上显示下拉内容。</p>
<div class="dropdown">
<img src="https://img.php.cn/upload/course/000/000/006/580837363b987802.jpg" alt="Trolltunga Norway" width="100" height="50">
<div class="dropdown-content">
<img src="https://img.php.cn/upload/course/000/000/006/580837363b987802.jpg" alt="Trolltunga Norway" width="400" height="200">
<div class="desc">PHP中文网（php.cn）</div>
</div>
</div>
</body>
</html>Run the program and try it
Next Section
