The border-top-width
CSS property sets the width of the top border of a box.
/* 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;
<line-width>
<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.
<line-width>where
<line-width> = <length> | thin | medium | thick
<div>Element 1</div> <div>Element 2</div>
div { border: 1px solid red; margin: 1em 0; } div:nth-child(1) { border-top-width: thick; } div:nth-child(2) { border-top-width: 2em; }
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. |
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-top-style is none or hidden
|
Animation type | a length |
Canonical order | the unique non-ambiguous order defined by the formal grammar |
Desktop | ||||||
---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | |
Basic support | 1 | 12 | 1 | 4 | 3.5 | 1 |
Mobile | |||||||
---|---|---|---|---|---|---|---|
Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | iOS Safari | Samsung Internet | |
Basic support | 2.3 | ? | Yes | 4 | 11 | 1 | ? |
border-left-width
, border-right-width
, border-bottom-width
, and border-width
.border
, border-top
, border-top-style
, and border-top-color
.
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/border-top-width