: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 Standard # selector-checked
Selectors Level 4 # checked

浏览器兼容性

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