border-bottom-width

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

CSS 属性 border-bottom-width 设置一个元素的底部边框宽度。

css
/* Keyword values */
border-bottom-width: thin;
border-bottom-width: medium;
border-bottom-width: thick;

/* <length> values */
border-bottom-width: 10em;
border-bottom-width: 3vmax;
border-bottom-width: 6px;

/* Global keywords */
border-bottom-width: inherit;
border-bottom-width: initial;
border-bottom-width: unset;
初始值medium
适用元素所有元素. It also applies to ::first-letter.
是否是继承属性否
计算值绝对长度；或如果 border-bottom-style 的值是 none 或 hidden，则为 0
动画类型a length

Syntax

Values

<br-width>

定义边框宽度，取值为非负的宽度值<length>或关键字。如果是关键字的话，其取值必须是以下之一：

thin 细边框
medium 中等边框
thick 粗边框

备注： 因为规范没有具体定义每个关键字对应的宽度值，所以实际显示效果依赖于实现。但是宽度值的取值一定遵循 thin ≤ medium ≤ thick 的规律且在单文档中是常数。

Formal syntax

border-bottom-width = 
  <line-width>  

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

Example

HTML

html
<div>Element 1</div>
<div>Element 2</div>

CSS

css
div {
  border: 1px solid red;
  margin: 1em 0;
}

div:nth-child(1) {
  border-bottom-width: thick;
}
div:nth-child(2) {
  border-bottom-width: 2em;
}

Result

Specifications

Specification
CSS Backgrounds and Borders Module Level 3
# the-border-width

Browser compatibility

BCD tables only load in the browser

See also