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:checked
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2015年7月.
: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" /> <label for="yes">Yes</label> <input type="radio" name="my-input" /> <label for="no">No</label></div><div> <input type="checkbox" name="my-checkbox" /> <label for="opt-in">Check me!</label></div><select name="my-select"> <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" /><table> <thead> <tr> <th>Column #1</th> <th>Column #2</th> <th>Column #3</th> </tr> </thead> <tbody> <tr> <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> <td>[more text]</td> <td>[more text]</td> <td>[more text]</td> </tr> <tr> <td>[more text]</td> <td>[more text]</td> <td>[more text]</td> </tr> </tbody></table><label for="expand-toggle">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 |