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
计算值绝对长度;或如果 border-bottom-style 的值是 nonehidden,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

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
border-bottom-width

Legend

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Full support
Full support

See also