:checked
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
:checked CSS 伪类选择器表示任何处于选中状态的radio(<input type="radio">), checkbox (<input type="checkbox">) 或 ("select") 元素中的option HTML 元素 ("option")。
css
/* 匹配任意被勾选/选中的 radio(单选按钮),checkbox(复选框),或者 option(select 中的一项) */ :checked { margin-left: 25px; border: 1px solid blue; } 用户通过勾选/选中元素或取消勾选/取消选中，来改变该元素的 :checked 状态。
备注： 因为浏览器经常将 <option> 视为可替换元素，因此不同的浏览器通过:checked伪类渲染出来的效果也不尽相同。
语法
css
:checked { /* CSS declarations */ } 示例
基础示例
HTML
html
<div> <input type="radio" name="my-input" id="yes" /> <label for="yes">Yes</label> <input type="radio" name="my-input" id="no" /> <label for="no">No</label> </div> <div> <input type="checkbox" name="my-checkbox" id="opt-in" /> <label for="opt-in">Check me!</label> </div> <select name="my-select" id="fruit"> <option value="opt1">Apples</option> <option value="opt2">Grapes</option> <option value="opt3">Pears</option> </select> CSS
css
div, select { margin: 8px; } /* Labels for checked inputs */ input:checked + label { color: red; } /* Radio element, when checked */ input[type="radio"]:checked { box-shadow: 0 0 0 3px orange; } /* Checkbox element, when checked */ input[type="checkbox"]:checked { box-shadow: 0 0 0 3px hotpink; } /* Option elements, when selected */ option:checked { box-shadow: 0 0 0 3px lime; color: red; } 结果
借用隐藏的 checkbox 来切换元素的样式（显示/隐藏）
这个例子利用了:checked伪类，让用户基于复选框的状态切换内容，而无需使用 JavaScript。
HTML
html
<input type="checkbox" id="expand-toggle" /> <table> <thead> <tr> <th>Column #1</th> <th>Column #2</th> <th>Column #3</th> </tr> </thead> <tbody> <tr class="expandable"> <td>[more text]</td> <td>[more text]</td> <td>[more text]</td> </tr> <tr> <td>[cell text]</td> <td>[cell text]</td> <td>[cell text]</td> </tr> <tr> <td>[cell text]</td> <td>[cell text]</td> <td>[cell text]</td> </tr> <tr class="expandable"> <td>[more text]</td> <td>[more text]</td> <td>[more text]</td> </tr> <tr class="expandable"> <td>[more text]</td> <td>[more text]</td> <td>[more text]</td> </tr> </tbody> </table> <label for="expand-toggle" id="expand-btn">Toggle hidden rows</label> CSS
css
/* Hide the toggle checkbox */ #expand-toggle { display: none; } /* Hide expandable content by default */ .expandable { visibility: collapse; background: #ddd; } /* Style the button */ #expand-btn { display: inline-block; margin-top: 12px; padding: 5px 11px; background-color: #ff7; border: 1px solid; border-radius: 3px; } /* Show hidden content when the checkbox is checked */ #expand-toggle:checked ~ * .expandable { visibility: visible; } /* Style the button when the checkbox is checked */ #expand-toggle:checked ~ #expand-btn { background-color: #ccc; } 结果
规范
| Specification |
|---|
| HTML # selector-checked |
| Selectors Level 4 # checked-pseudo |