---
title: margin-right
slug: Web/CSS/margin-right
tags:
  - CSS
  - CSS 属性
translation_of: Web/CSS/margin-right
---
<p>{{CSSRef}}</p>

<h2 id="Summary" name="Summary">摘要</h2>

<p><img alt="The effect of the CSS margin-right property on the element box" src="/files/4041/margin-right.svg" style="border: solid 1px; float: left; height: 200px; margin-bottom: 1em; margin-right: 1em; width: 400px;"><strong><code>margin-right</code></strong>  属性 设置与元素相关联的盒子模型的右外边距。这个值可以为负值。</p>

<p><span class="seoSummary">竖直排列相邻的两个盒子模型的外边距会重叠，称为 <a href="https://developer.mozilla.org/en-US/docs/CSS/margin_collapsing" title="/en-US/docs/CSS/margin_collapsing"><em>margin collapsing</em></a>.</span></p>

<p>{{cssinfo}}</p>

<h2 id="Syntax" name="Syntax">语法</h2>

<pre class="brush:css">/* &lt;length&gt; values */
margin-right: 20px;        /* An absolute length */
margin-right: 1em;         /* A length relative to the text size */
margin-right: 5%;          /* A margin relative to the nearest block container's width */

/* Keyword values */
margin-right: auto;

/* Global values */
margin-right: inherit;
margin-right: initial;
margin-right: unset;
</pre>

<h3 id="Values" name="Values">值</h3>

<dl>
 <dt><code>&lt;length&gt;</code></dt>
 <dd>一个固定宽度 {{cssxref("&lt;length&gt;")}}值: 可以是一个绝对宽度，e.g. in <code>px</code>, 也可以是一个相对宽度， e.g. in <code>em</code>, 或者相对视窗的大小，e.g. in <code>vh</code>.</dd>
 <dt><code>&lt;percentage&gt;</code></dt>
 <dd>以百分比为单位的margin值，计算时是相对于其最近的父级容器的宽度。</dd>
 <dt><code>auto</code></dt>
 <dd>auto关键词表示在当前布局模式下，浏览器根据接收的左边距自动计算出外边距。如果有几组margin-left和margin-right 设置为auto，那么最后计算的空间分布，会根据display，float，position属性，自动生成以下几种情况：
 <table class="standard-table">
  <thead>
   <tr>
    <th scope="col">Value of {{cssxref("display")}}</th>
    <th scope="col">Value of {{cssxref("float")}}</th>
    <th scope="col">Value of {{cssxref("position")}}</th>
    <th scope="col">Computed value of <code>auto</code></th>
    <th scope="col">Comment</th>
   </tr>
  </thead>
  <tbody>
   <tr>
    <th><code>inline</code>, <code>inline-block</code>, <code>inline-table</code></th>
    <th><em>any</em></th>
    <th><code>static</code> or <code>relative</code></th>
    <td><code>0</code></td>
    <td>Inline layout mode</td>
   </tr>
   <tr>
    <th><code>block</code>, <code>inline</code>, <code>inline-block</code>, <code>block</code>, <code>table</code>, <code>inline-table</code>, <code>list-item</code>, <code>table-caption</code></th>
    <th><em>any</em></th>
    <th><code>static</code> or <code>relative</code></th>
    <td><code>0</code>, except if both <code>margin-left</code> and <code>margin-right</code> are set to <code>auto</code>. In this case, it is set to the value centering the element inside its parent.</td>
    <td>Block layout mode</td>
   </tr>
   <tr>
    <th><code>block</code>, <code>inline</code>, <code>inline-block</code>, <code>block</code>, <code>table</code>, <code>inline-table</code>, <code>list-item</code>, <code>table-caption</code></th>
    <th><code>left</code> or <code>right</code></th>
    <th><code>static</code> or <code>relative</code></th>
    <td><code>0</code></td>
    <td>Block layout mode (floating element)</td>
   </tr>
   <tr>
    <th><em>any </em><code>table-*</code><em>, except </em><code>table-caption</code></th>
    <th><em>any</em></th>
    <th><em>any</em></th>
    <td><code>0</code></td>
    <td>Internal <code>table-*</code> elements don't have margins, use {{ cssxref("border-spacing") }} instead</td>
   </tr>
   <tr>
    <th><em>any, except <code>flex</code>,</em> <code>inline-flex</code><em>, or </em><code>table-*</code></th>
    <th><em>any</em></th>
    <th><em><code>fixed</code></em> or <code>absolute</code></th>
    <td><code>0</code>, except if both <code>margin-left</code> and <code>margin-right</code> are set to <code>auto</code>. In this case, it is set to the value centering the border area inside the available <code>width</code>, if fixed.</td>
    <td>Absolutely positioned layout mode</td>
   </tr>
   <tr>
    <th><code>flex</code>, <code>inline-flex</code></th>
    <th><em>any</em></th>
    <th><em>any</em></th>
    <td><code>0</code>, except if there is any positive horizontal free space. In this case, it is evenly distributed to all horizontal <code>auto</code> margins.</td>
    <td>Flexbox layout mode</td>
   </tr>
  </tbody>
 </table>
 </dd>
</dl>

<h3 id="形式语法">形式语法</h3>

<pre class="syntaxbox">{{csssyntax}}</pre>

<h2 id="Examples" name="Examples">实例</h2>

<pre class="eval">.content { margin-right: 5%; }
.sidebox { margin-right: 10px; }
.logo    { margin-right: -5px; }
</pre>

<h2 id="Specifications" name="Specifications">说明</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('CSS3 Box', '#the-margin', 'margin-right') }}</td>
   <td>{{ Spec2('CSS3 Box') }}</td>
   <td>No significant change</td>
  </tr>
  <tr>
   <td>{{ SpecName('CSS3 Transitions', '#animatable-css', 'margin-right') }}</td>
   <td>{{ Spec2('CSS3 Transitions') }}</td>
   <td>Defines <code>margin-right</code> as animatable.</td>
  </tr>
  <tr>
   <td>{{SpecName('CSS3 Flexbox', '#item-margins', 'margin-right')}}</td>
   <td>{{ Spec2('CSS3 Flexbox') }}</td>
   <td>Defines the behavior of <code>margin-right</code> on flex items.</td>
  </tr>
  <tr>
   <td>{{ SpecName('CSS2.1', 'box.html#margin-properties', 'margin-right') }}</td>
   <td>{{ Spec2('CSS2.1') }}</td>
   <td>Removes its effect on inline elements.</td>
  </tr>
  <tr>
   <td>{{ SpecName('CSS1', '#margin-right', 'margin-right') }}</td>
   <td>{{ Spec2('CSS1') }}</td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>

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

<p>{{CompatibilityTable}}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari (WebKit)</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>1.0</td>
   <td>{{ CompatGeckoDesktop("1") }}</td>
   <td>3.0</td>
   <td>3.5</td>
   <td>1.0 (85)</td>
  </tr>
  <tr>
   <td><code>auto</code> value</td>
   <td>1.0</td>
   <td>{{ CompatGeckoDesktop("1") }}</td>
   <td>6.0 (strict mode)</td>
   <td>3.5</td>
   <td>1.0 (85)</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Phone</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>1.0</td>
   <td>{{ CompatGeckoMobile("1") }}</td>
   <td>6.0</td>
   <td>6.0</td>
   <td>1.0</td>
  </tr>
 </tbody>
</table>
</div>