📚 CSS 知识图谱 新特性、属性、布局、响应式、动画
Home Page: https://tsejx.github.io/css-guidebook/
关于 CSS 详细信息（包括语法解释、兼容性和示例等）推荐查询以下网站：
![dependabot[bot] avatar](https://avatars.githubusercontent.com/in/29110?v=4 "dependabot[bot]")
CSS3中的伪类选择器例如:hover，:before，:after在已经在前端开发中被广泛使用，但是可能开发者还不太熟悉:checked这个伪类选择器。本文将介绍:checked这个伪类选择器以及如何使用它写出更加有优雅的代码。
:checked伪类选择器顾名思义，表示的是type="checkbox"的input元素被选中的状态。在前端开发中，我们常用:hover伪类来设置鼠标悬浮时的样式，而由于checked状态的改变需要用户进行点击操作，使用:checked伪类，我们则可以设置鼠标点击后的状态。在使用zepto、jQuery库时，有一个经常使用的方法toggle用来隐藏和再现页面上的某个元素，了解:checked伪类的定义之后，我们完全可以用纯CSS实现toggle效果。
首先定义页面结构：
<style>
.toggle-item{
width: 100px;
height: 100px;
background-color: pink;
}
</style>
<div class="toggle">
<input id="toggle-trigger" type="checkbox" />
<div class="toggle-item"></div>
</div>
接着，我们对#toggle-trigger的选中态进行设置
#toggle-trigger:not(checked) ~ .toggle-item{
display: block;
}
#toggle-trigger:checked ~ .toggle-item{
display: none;
}
此时，我们通过点击选中或者取消选中checkbox，就能对.toggle-item进行隐藏和再现。
但是我们想跟进一步，把toggle-trigger的范围扩展到checkbox之外，因为在展现toggle效果时，触发toggle的部分并不局限于checkbox一种形式。这时我们只需要使用label标签即可，label标签有一个for属性，通过设置for属性，可以将label标签指向特定的input元素，同时将checkbox隐藏，既可以达到点击label标签来触发toggle的效果。
<style>
.toggle-item{
width: 100px;
height: 100px;
background-color: pink;
}
#toggle-trigger {
display: none;
}
#toggle-trigger ~ :not(checked) ~ .toggle-item{
display: block;
}
#toggle-trigger:checked ~ .toggle-item{
display: none;
}
</style>
<div class="toggle">
<label for="toggle-trigger">触发器</label>
<input id="toggle-trigger" type="checkbox" />
<div class="toggle-item"></div>
</div>
根据caniuse的数据，:checked伪类的支持程度基本达到了100%。在下一个项目里面，你会愿意使用它嘛？
参考文章
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
An Open Source Machine Learning Framework for Everyone
Django
The Web framework for perfectionists with deadlines.
Laravel
A PHP framework for web artisans
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
Some thing interesting about web. New door for the world.
A server is a program made to process requests and deliver data to clients.
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Some thing interesting about visualization, use data art
Some thing interesting about game, make everyone happy.
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
Microsoft
Open source projects and samples from Microsoft.
Google
Google ❤️ Open Source for everyone.
Alibaba
Alibaba Open Source for everyone
D3
Data-Driven Documents codes.
Tencent
China tencent open source team.