The border-top CSS property is a shorthand that sets the values of border-top-color, border-top-style, and border-top-width. These properties describe the top border of elements.
The three values of the shorthand property can be specified in any order, and one or two of them may be omitted.
As with all shorthand properties, border-top always sets the values of all of the properties that it can set, even if they are not specified. It sets those that are not specified to their default values. This means that:
border-top-style: dotted; border-top: thick green;
is actually the same as
border-top-style: dotted; border-top: none thick green;
and the value of border-top-style given before border-top is ignored.
Since the default value of border-top-style is none, not specifying the border-style part of the value means that the property specifies its default value which is none and means no border.
| Initial value | as each of the properties of the shorthand:
|
|---|---|
| Applies to | all elements. It also applies to ::first-letter. |
| Inherited | no |
| Media | visual |
| Computed value | as each of the properties of the shorthand:
|
| Animation type | as each of the properties of the shorthand:
|
| Canonical order | order of appearance in the formal grammar of the values |
border-top: 1px; border-top: 2px dotted; border-top: medium dashed green;
<br-width> border-top-width.<br-style> border-top-style.<color> border-top-color.<br-width> || <br-style> || <color>where
<br-width> = <length> | thin | medium | thick
<br-style> = none | hidden | dotted | dashed | solid | double | groove | ridge | inset | outset
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>where
<rgb()> = rgb( <rgb-component>#{3} )
<rgba()> = rgba( <rgb-component>#{3} , <alpha-value> )
<hsl()> = hsl( <hue>, <percentage>, <percentage> )
<hsla()> = hsla( <hue>, <percentage>, <percentage>, <alpha-value> )
<named-color> = transparent | aliceblue | antiquewhite | aqua | aquamarine | azure | beige | bisque | black | blanchedalmond | blue | blueviolet | brown | burlywood | cadetblue | chartreuse | chocolate | coral | cornflowerblue | cornsilk | crimson | cyan | darkblue | darkcyan | darkgoldenrod | darkgray | darkgreen | darkgrey | darkkhaki | darkmagenta | darkolivegreen | darkorange | darkorchid | darkred | darksalmon | darkseagreen | darkslateblue | darkslategray | darkslategrey | darkturquoise | darkviolet | deeppink | deepskyblue | dimgray | dimgrey | dodgerblue | firebrick | floralwhite | forestgreen | fuchsia | gainsboro | ghostwhite | gold | goldenrod | gray | green | greenyellow | grey | honeydew | hotpink | indianred | indigo | ivory | khaki | lavender | lavenderblush | lawngreen | lemonchiffon | lightblue | lightcoral | lightcyan | lightgoldenrodyellow | lightgray | lightgreen | lightgrey | lightpink | lightsalmon | lightseagreen | lightskyblue | lightslategray | lightslategrey | lightsteelblue | lightyellow | lime | limegreen | linen | magenta | maroon | mediumaquamarine | mediumblue | mediumorchid | mediumpurple | mediumseagreen | mediumslateblue | mediumspringgreen | mediumturquoise | mediumvioletred | midnightblue | mintcream | mistyrose | moccasin | navajowhite | navy | oldlace | olive | olivedrab | orange | orangered | orchid | palegoldenrod | palegreen | paleturquoise | palevioletred | papayawhip | peachpuff | peru | pink | plum | powderblue | purple | rebeccapurple | red | rosybrown | royalblue | saddlebrown | salmon | sandybrown | seagreen | seashell | sienna | silver | skyblue | slateblue | slategray | slategrey | snow | springgreen | steelblue | tan | teal | thistle | tomato | turquoise | violet | wheat | white | whitesmoke | yellow | yellowgreen
<deprecated-system-color> = ActiveBorder | ActiveCaption | AppWorkspace | Background | ButtonFace | ButtonHighlight | ButtonShadow | ButtonText | CaptionText | GrayText | Highlight | HighlightText | InactiveBorder | InactiveCaption | InactiveCaptionText | InfoBackground | InfoText | Menu | MenuText | Scrollbar | ThreeDDarkShadow | ThreeDFace | ThreeDHighlight | ThreeDLightShadow | ThreeDShadow | Window | WindowFrame | WindowTextwhere
<rgb-component> = <integer> | <percentage>
<alpha-value> = <number>
<hue> = <number>
element {
border-top: 1px solid #000;
}
| Specification | Status | Comment |
|---|---|---|
| CSS Backgrounds and Borders Module Level 3 The definition of 'border-top' in that specification. | Candidate Recommendation | No direct changes, though the modification of values for the border-top-color do apply to it. |
| CSS Level 2 (Revision 1) The definition of 'border-top' in that specification. | Recommendation | No significant changes |
| CSS Level 1 The definition of 'border-top' in that specification. | Recommendation | Initial definition |
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|---|
| Basic support | 1.0 | (Yes) | 1.0 (1.7 or earlier) | 4 | 3.5 | 1.0 (85) |
| Feature | Android | Edge | Firefox Mobile (Gecko) | IE Phone | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | 1.0 | (Yes) | 1.0 (1.0) | (Yes) | (Yes) | (Yes) |
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https://developer.mozilla.org/en-US/docs/Web/CSS/border-top