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---
title: ':focus'
slug: 'Web/CSS/:focus'
tags:
- CSS
- Layout
- Reference
- Web
- 伪类
translation_of: 'Web/CSS/:focus'
---
<p>{{CSSRef}}</p>
<p>CSS<a href="/en/CSS/Pseudo-classes" title="Pseudo-classes">伪类</a> <code>:focus</code>表示获得焦点的元素（如表单输入）。当用户点击或触摸元素或通过键盘的 “tab” 键选择它时会被触发。</p>
<pre class="brush: css">/* Selects any <input> when focused */
input:focus {
color: red;
}</pre>
<div class="note">
<p><strong>提示：</strong>此伪类仅适用于焦点元素本身。如果要选择包含焦点元素的元素，请使用{{cssxref(":focus-within")}} 。</p>
</div>
<h2 id="语法">语法</h2>
{{csssyntax}}
<h2 id="Example">Example</h2>
<h3 id="HTML">HTML</h3>
<pre class="brush: html"><input class="red-input" value="I'll be red when focused."><br>
<input class="blue-input" value="I'll be blue when focused."></pre>
<h3 id="CSS">CSS</h3>
<pre class="brush: css">.red-input:focus {
background: yellow;
color: red;
}
.blue-input:focus {
background: yellow;
color: blue;
}</pre>
<h3 id="结果">结果</h3>
<p>{{EmbedLiveSample('Example')}}</p>
<h2 id="规范">规范</h2>
<table class="standard-table">
<thead>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
</thead>
<tbody>
<tr>
<td>{{SpecName('HTML WHATWG', 'scripting.html#selector-focus', ':focus')}}</td>
<td>{{Spec2('HTML WHATWG')}}</td>
<td>Defines HTML-specific semantics.</td>
</tr>
<tr>
<td>{{SpecName('CSS4 Selectors', '#focus-pseudo', ':focus')}}</td>
<td>{{Spec2('CSS4 Selectors')}}</td>
<td>No change.</td>
</tr>
<tr>
<td>{{SpecName('CSS3 Selectors', '#the-user-action-pseudo-classes-hover-act', ':focus')}}</td>
<td>{{Spec2('CSS3 Selectors')}}</td>
<td>No change.</td>
</tr>
<tr>
<td>{{SpecName('CSS2.1', 'selector.html#dynamic-pseudo-classes', ':focus')}}</td>
<td>{{Spec2('CSS2.1')}}</td>
<td>Initial definition.</td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p>{{Compat("css.selectors.focus")}}</p>
<div id="compat-mobile"> </div>
<h2 id="参考">参考</h2>
<ul>
<li>{{cssxref(":focus-within")}}</li>
</ul>
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