border-bottom-width

The border-bottom-width CSS property sets the width of the bottom border of a box.

Initial value	medium
Applies to	all elements. It also applies to ::first-letter.
Inherited	no
Media	visual
Computed value	the absolute length or 0 if border-bottom-style is none or hidden
Animation type	a length
Canonical order	the unique non-ambiguous order defined by the formal grammar

Syntax

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

/* A keyword */
border-bottom-width: thin;
border-bottom-width: medium;
border-bottom-width: thick;

border-bottom-width: inherit;

Values

<br-width>

Is either a non-negative explicit <length> value or a keyword denoting the thickness of the bottom border. The keyword must be one of the following values:

thin		A thin border
medium		A medium border
thick		A thick border

The specification doesn't precisely define the thickness of each of the keywords, which is therefore implementation specific. Nevertheless, it requests that the thickness does follow the thin ≤ medium ≤ thick inequality and that the values are constant on a single document.

inherit

Represents the calculated value of the border-bottom-width of the parent's element.

Formal syntax

<br-width>
where 
<br-width> = <length> | thin | medium | thick

Examples

element { 
    border-bottom-width: thin;
    border-bottom-style: solid;
    border-bottom-color: #000;
}

Specifications

Specification	Status	Comment
CSS Backgrounds and Borders Module Level 3 The definition of 'border-bottom-width' in that specification.	Candidate Recommendation	No significant change
CSS Level 2 (Revision 1) The definition of 'border-bottom-width' in that specification.	Recommendation	Initial definition

Browser compatibility

See also

• The other border-width-related CSS properties: border-left-width, border-right-width, border-top-width, and border-width
• The other border-bottom-related CSS properties: border, border-bottom, border-bottom-style, and border-bottom-color.