---
title: width
slug: Web/CSS/@media/width
tags:
  - '@media'
  - CSS
  - NeedsBrowserCompatibility
  - Reference
  - media feature
translation_of: Web/CSS/@media/width
---
<div>{{cssref}}</div>

<p><code><font face="Open Sans, arial, x-locale-body, sans-serif"><span style="background-color: #ffffff;">可以使用</span></font><strong>width</strong></code> <a href="/en-US/docs/CSS">CSS</a> {{cssxref("@media")}} 基于{{glossary("viewport")}}宽度(或页面框，用于<a href="/en-US/docs/Web/CSS/Paged_media">paged media</a>)应用样式。</p>

<h2 id="语法"><strong>语法</strong></h2>

<p>该<code>width</code>特性被指定为{{cssxref("&lt;length&gt;")}}，表示viewport宽度的值。这是一个范围特性，也就是说，您也可以使用前缀<strong><code>min-width</code></strong>和<code><strong>max-width</strong></code>分别查询最小值和最大值。</p>

<h2 id="例子"><strong>例子</strong></h2>

<h3 id="HTML">HTML</h3>

<pre class="brush: html">&lt;div&gt;改变viewport的宽度的同时，观察这个元素的变化。&lt;/div&gt;</pre>

<h3 id="CSS">CSS</h3>

<pre class="brush: css">/* 精确宽度 */
@media (width: 360px) {
  div {
    color: red;
  }
}

/* 最小宽度 */
@media (min-width: 35rem) {
  div {
    background: yellow;
  }
}

/* 最大宽度 */
@media (max-width: 50rem) {
  div {
    border: 2px solid blue;
  }
}
</pre>

<h3 id="结果">结果</h3>

<p>{{EmbedLiveSample('Example','90%')}}</p>

<h2 id="规范"><strong>规范</strong></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('CSS4 Media Queries', '#width', 'width')}}</td>
   <td>{{Spec2('CSS4 Media Queries')}}</td>
   <td>The value can now be negative, in which case it computes to false.</td>
  </tr>
  <tr>
   <td>{{SpecName('CSS3 Media Queries', '#width', 'width')}}</td>
   <td>{{Spec2('CSS3 Media Queries')}}</td>
   <td>Initial definition. The value must be nonnegative.</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility" name="Browser_compatibility"><strong>浏览器兼容性</strong></h2>

{{Compat("css.at-rules.media.width")}}