语法
:checked {
css declarations;
}
在以下示例中，选中复选框以查看其工作原理。
带有 <div> 标签的 :checked 选择器示例：
<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
div {
margin: 10px;
font-size: 20px;
}
input:checked + label {
color: #000;
}
input[type="radio"]:checked {
box-shadow: 0 0 0 4px #8ebf42;
}
/* Checkbox element, when checked */
input[type="checkbox"]:checked {
box-shadow: 0 0 0 3px #1c87c9;
}
</style>
</head>
<body>
<h2>:checked selector example</h2>
<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!</label>
</div>
</body>
</html>
带有 <table>、<tr>、<th>、<td> 标签的 :checked 选择器示例：
<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
table,tr,th,td {
border: 1px solid #ccc;
text-align: center;
border-collapse: collapse;
padding: 8px;
}
#toggle {
display: none;
}
.expandable {
visibility: collapse;
background: #1c87c9;
}
#btn {
display: inline-block;
margin-top: 15px;
padding: 10px 20px;
background-color: #8ebf42;
color: #fff;
cursor: pointer;
border-radius: 3px;
}
#toggle:checked ~ * .expandable {
visibility: visible;
}
#toggle:checked ~ #btn {
background-color: #ccc;
}
</style>
</head>
<body>
<h2>::checked selector example</h2>
<input type="checkbox" id="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>[text]</td>
<td>[text]</td>
<td>[text]</td>
</tr>
<tr class="expandable">
<td>[more text]</td>
<td>[more text]</td>
<td>[more text]</td>
</tr>
<tr>
<td>[text]</td>
<td>[text]</td>
<td>[text]</td>
</tr>
<tr class="expandable">
<td>[more text]</td>
<td>[more text]</td>
<td>[more text]</td>
</tr>
</tbody>
</table>
<label for="toggle" id="btn">Click here!</label>
</body>
</html>
:checked 选择器的例子：
<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
input[type=checkbox] {
vertical-align:middle;
}
input[type=checkbox] + label {
color: #999999;
font-style: normal;
}
input[type=checkbox]:checked + label {
color: #8ebf42;
font-style: italic;
font-weight:bold;
}
</style>
</head>
<body>
<h2>:checked selector example</h2>
<form>
<input type="checkbox" id="css" name="css">
<label for="css">Here is CSS example.</label>
</form>
</body>
</html>
所以， :checked 伪类可用于使表单更易于访问并构建具有隐藏输入及其可见标签的交互式小部件。
:checked 伪类用于选择处于选中状态的元素。
它仅与 <input>（仅用于单选按钮和复选框）和 <option> 元素有关。
复选框和单选元素可以由用户切换“on”和“off”。
日期：2020-06-02 22:14:21 来源：oir作者：oir