The border-top-width
CSS property sets the width of the top border of an element.
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Syntax
/* Keyword values */ border-top-width: thin; border-top-width: medium; border-top-width: thick; /* <length> values */ border-top-width: 10em; border-top-width: 3vmax; border-top-width: 6px; /* Global keywords */ border-top-width: inherit; border-top-width: initial; border-top-width: unset;
Values
<line-width>
- Defines the width of the border, either as an explicit nonnegative
<length>
or a keyword. If it's a keyword, it must be one of the following values:thin
A thin border medium
A medium border thick
A thick border Note: Because the specification doesn't define the exact thickness denoted by each keyword, the precise result when using one of them is implementation-specific. Nevertheless, they always follow the pattern
thin ≤ medium ≤ thick
, and the values are constant within a single document.
Formal definition
Initial value | medium |
---|---|
Applies to | all elements. It also applies to ::first-letter . |
Inherited | no |
Computed value | the absolute length or 0 if border-top-style is none or hidden |
Animation type | a length |
Formal syntax
<line-width>where
<line-width> = <length> | thin | medium | thick
Examples
HTML
<div>Element 1</div> <div>Element 2</div>
CSS
div { border: 1px solid red; margin: 1em 0; } div:nth-child(1) { border-top-width: thick; } div:nth-child(2) { border-top-width: 2em; }
Result
Specifications
Specification | Status | Comment |
---|---|---|
CSS Backgrounds and Borders Module Level 3 The definition of 'border-top-width' in that specification. |
Candidate Recommendation | No significant change. |
CSS Level 2 (Revision 1) The definition of 'border-top-width' in that specification. |
Recommendation | No significant change. |
CSS Level 1 The definition of 'border-top-width' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
border-top-width | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 3.5 | Safari Full support 1 | WebView Android Full support 2.3 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 |
Legend
- Full support
- Full support
See also
- The other border-width-related CSS properties:
border-left-width
,border-right-width
,border-bottom-width
, andborder-width
. - The other border-top-related CSS properties:
border
,border-top
,border-top-style
, andborder-top-color
.