---
title: Dropdowns
localeTitle: 下拉菜单
---
## 下拉菜单
下拉列表在CSS中用于隐藏按钮内的预定义列表。
例子:
```html
```
然后你应该在CSS中自定义类
```css
.dropdown {
position: relative;
display: inline-block;
}
.dropbtn {
background-color: red;
padding: 10px;
}
.dropdown-content {
display: none;
position: absolute;
}
.dropdown:hover .dropdown-content {
display:block;
}
```
您需要单独的div类来创建按钮,而另一个div用于分隔按钮所包含的列表。
#### 一个例子
```html
```
```css
#myNav1 {
height: 0;
width: 50%;
position: fixed;
z-index: 6;
top: 0;
left: 0;
background-color: #ffff;
overflow: hidden;
transition: 0.3s;
opacity: 0.85;
}
#myNav2 {
height: 0;
width: 50%;
position: fixed;
z-index: 6;
bottom: 0;
right: 0;
background-color: #ffff;
overflow: hidden;
transition: 0.3s;
opacity: 0.85;
}
.overlay-content {
position: relative;
width: 100%;
text-align: center;
margin-top: 30px;
}
#myNav1-content{
top: 12%;
left: 5%;
display: none;
}
#myNav2-content{
top: 12%;
right: 10%;
display: none;
}
```
#### 更多信息:
* W3 School Dropdown Hover Button: [链接到W3学校](https://www.w3schools.com/howto/howto_css_dropdown.asp)
* W3学校课程: [连结W3学校](https://www.w3schools.com/css/css_dropdowns.asp)