--- title: margin-bottom slug: Web/CSS/margin-bottom tags: - CSS - CSS属性 - 参考 translation_of: Web/CSS/margin-bottom --- <div>{{CSSRef}}</div> <h2 id="Summary" name="Summary">Summary</h2> <p><img alt="The effect of the CSS margin-bottom property on the element box" src="https://mdn.mozillademos.org/files/12980/margin-bottom%20explained.svg" style="border: 1px solid; float: left; height: 252px; margin-bottom: 1em; margin-right: 1em; padding-right: 0.5em; width: 368px;"></p> <p><span class="seoSummary">CSS的<code> margin-bottom 属性用于设置元素的底部外边距,允许设置负数值。一个正数值将让它相对于正常流与邻近块更远,而负数值将使得更近。</code></span></p> <p><span class="seoSummary">该属性对于<em>不可替代(non-replaced 元素在规范中有概念,请自行搜索)</em>的行级元素没有效果,比如: {{HTMLElement("tt")}} 或者 {{HTMLElement("span")}}.</span></p> <p>{{cssinfo}}</p> <h2 id="Syntax" name="Syntax">语法</h2> <pre class="brush:css">/* <length> values */ margin-bottom: 10px; /* 一个绝对的长度值 */ margin-bottom: 1em; /* A length relative to the text size */ margin-bottom: 5%; /* A margin relative to the nearest block container's width */ /* Keyword values */ margin-bottom: auto; /* Global values */ margin-bottom: inherit; margin-bottom: initial; margin-bottom: unset; </pre> <h3 id="Values" name="Values">值</h3> <dl> <dt><code><length></code></dt> <dd>定义了一个确定的宽度值,参见 {{cssxref("<length>")}} 以了解更多可能的值。</dd> <dt><code><percentage></code></dt> <dd>{{cssxref("<percentage>")}} 始终与包含该元素的<strong>容器宽度</strong>有关。</dd> <dt><code>auto</code></dt> <dd>由浏览器自己选择一个合适的值。参见 {{cssxref("margin")}}。</dd> </dl> <h3 id="正式语法">正式语法</h3> {{csssyntax}} <h2 id="Example" name="Example">样例</h2> <h3 id="HTML">HTML</h3> <pre class="brush: html"><div class="container"> <div class="box0">Box 0</div> <div class="box1">Box 1</div> <div class="box2">Box one's negative margin pulls me up</div> </div></pre> <h3 id="CSS">CSS</h3> <p>用于设置<code> div </code>的<code> margin-bottom </code>和<code> height </code>的 CSS代码</p> <pre class="brush: css">.box0 { margin-bottom:1em; height:3em; } .box1 { margin-bottom:-1.5em; height:4em; } .box2 { border:1px dashed black; border-width:1px 0; margin-bottom:2em; } </pre> <p>为了使<code> margin </code>产生的影响更明显,添加了一些<code> container </code>和<code> div </code>的样式定义</p> <pre class="brush: css">.container { background-color:orange; width:320px; border:1px solid black; } div { width:320px; background-color:gold; }</pre> <p>{{ EmbedLiveSample('Example',350,200) }}</p> <h2 id="规范">规范</h2> <table class="standard-table"> <thead> <tr> <th scope="col">规范</th> <th scope="col">状态</th> <th scope="col">注释</th> </tr> </thead> <tbody> <tr> <td>{{SpecName('CSS3 Box', '#margin-bottom', 'margin-bottom')}}</td> <td>{{Spec2('CSS3 Box')}}</td> <td>无明显变化</td> </tr> <tr> <td>{{SpecName('CSS3 Transitions', '#animatable-css', 'margin-bottom')}}</td> <td>{{Spec2('CSS3 Transitions')}}</td> <td>将 <code>margin-bottom</code> 定义为可动画化</td> </tr> <tr> <td>{{SpecName('CSS2.1', 'box.html#margin-properties', 'margin-bottom')}}</td> <td>{{Spec2('CSS2.1')}}</td> <td>移除了对内联元素的影响</td> </tr> <tr> <td>{{SpecName('CSS1', '#margin-bottom', 'margin-bottom')}}</td> <td>{{Spec2('CSS1')}}</td> <td>初始定义</td> </tr> </tbody> </table> <h2 id="Browser_Compatibility" name="Browser_Compatibility">浏览器兼容性</h2> {{Compat("css.properties.margin-bottom")}}