:focus-within
:focus-within CSS 伪类匹配元素,如果该元素或其任何后代元素获得焦点。换句话说,它表示一个元素本身与 :focus 伪类匹配,或者其后代元素与 :focus 匹配。(这包括影子 DOM 中的后代元素。)
试一试
label {
display: block;
margin-top: 1em;
}
label:focus-within {
font-weight: bold;
}
<form>
<p>Which flavor would you like to order?</p>
<label>Full Name: <input name="firstName" type="text" /></label>
<label
>Flavor:
<select name="flavor">
<option>Cherry</option>
<option>Green Tea</option>
<option>Moose Tracks</option>
<option>Mint Chip</option>
</select>
</label>
</form>
语法
css
:focus-within {
/* ... */
}
示例
在此示例中,当任一文本输入获得焦点时,表单将获得特殊的着色样式。
HTML
html
<p>Try typing into this form.</p>
<form>
<label for="given_name">Given Name:</label>
<input id="given_name" type="text" />
<br />
<label for="family_name">Family Name:</label>
<input id="family_name" type="text" />
</form>
CSS
css
form {
border: 1px solid;
color: gray;
padding: 4px;
}
form:focus-within {
background: #ffff88;
color: black;
}
input {
margin: 4px;
}
结果
规范
| 规范 |
|---|
| 选择器 Level 4 # the-focus-within-pseudo |
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