outline-width

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2017.

outline-width CSS 属性设置元素轮廓的粗细。轮廓是绘制在元素周围的线，位于 border 之外。

尝试一下

outline-width: 12px;

outline-width: thin;

outline-width: medium;

outline-width: thick;

<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element">
    This is a box with an outline around it.
  </div>
</section>

#example-element {
  outline: 0.75em solid;
  padding: 0.75em;
  width: 80%;
  height: 100px;
}

在定义轮廓的外观时，通常使用简写属性 outline 更为方便。

语法

css
/* 关键字值 */
outline-width: thin;
outline-width: medium;
outline-width: thick;

/* <length> 值 */
outline-width: 1px;
outline-width: 0.1em;

/* 全局值 */
outline-width: inherit;
outline-width: initial;
outline-width: revert;
outline-width: revert-layer;
outline-width: unset;

outline-width 属性的值可以是以下列表的任意一项。

值

<length>

轮廓的宽度指定为 <length>。

thin

取决于用户代理。通常等同于桌面浏览器的 1px（包括 Firefox）。

medium

取决于用户代理。通常等同于桌面浏览器的 3px（包括 Firefox）。

thick

取决于用户代理。通常等同于桌面浏览器的 5px（包括 Firefox）。

形式定义

初始值medium
适用元素所有元素
是否是继承属性否
计算值绝对长度；如果指定关键词为 none，则计算值为 0
动画类型a length

形式语法

outline-width = 
  <line-width>  

<line-width> = 
  <length [0,∞]>  |
  thin            |
  medium          |
  thick

示例

设置元素的轮廓宽度

HTML

html
<span id="thin">细</span>
<span id="medium">中等</span>
<span id="thick">粗</span>
<span id="twopixels">2px</span>
<span id="oneex">1ex</span>
<span id="em">1.2em</span>

CSS

css
span {
  outline-style: solid;
  display: inline-block;
  margin: 20px;
}

#thin {
  outline-width: thin;
}

#medium {
  outline-width: medium;
}

#thick {
  outline-width: thick;
}

#twopixels {
  outline-width: 2px;
}

#oneex {
  outline-width: 1ex;
}

#em {
  outline-width: 1.2em;
}

结果

规范

Specification
CSS Basic User Interface Module Level 4
# outline-width

浏览器兼容性

参见