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The border-left CSS property is a shorthand that sets the values of border-left-width, border-left-style, and border-left-color. These properties describe an element's left border.

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-left 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-left-style: dotted;
border-left: thick green;

... is actually the same as ...

border-left-style: dotted;
border-left: none thick green;

... and the value of border-left-style given before border-left is ignored. Since the default value of border-left-style is none, not specifying the border-style part results in no border.

Syntax

border-left: 1px;
border-left: 2px dotted;
border-left: medium dashed green;

The three values of the shorthand property can be specified in any order, and one or two of them may be omitted.

Values

<br-width> 
See border-left-width.
<br-style> 
See border-left-style.
<color>
See border-left-color.

Formal syntax

<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( <percentage>{3} [ / <alpha-value> ]? ) | rgb( <number>{3} [ / <alpha-value> ]? ) | rgb( <percentage>#{3} , <alpha-value>? ) | rgb( <number>#{3} , <alpha-value>? )
<rgba()> = rgba( <percentage>{3} [ / <alpha-value> ]? ) | rgba( <number>{3} [ / <alpha-value> ]? ) | rgba( <percentage>#{3} , <alpha-value>? ) | rgba( <number>#{3} , <alpha-value>? )
<hsl()> = hsl( <hue> <percentage> <percentage> [ / <alpha-value> ]? ) | hsl( <hue>, <percentage>, <percentage>, <alpha-value>? )
<hsla()> = hsla( <hue> <percentage> <percentage> [ / <alpha-value> ]? ) | hsla( <hue>, <percentage>, <percentage>, <alpha-value>? )

where
<alpha-value> = <number> | <percentage>
<hue> = <number> | <angle>

Example

<div>
  This box has a border on the left side.
</div>
div {
  border-left: 4px dashed blue;
  background-color: gold;
  height: 100px;
  width: 100px;
  font-weight: bold;
  text-align: center;
}

Specifications

Specification Status Comment
CSS Backgrounds and Borders Module Level 3
The definition of 'border-left' in that specification.
Candidate Recommendation No direct changes, though the modification of values for the border-left-color do apply to it.
CSS Level 2 (Revision 1)
The definition of 'border-left' in that specification.
Recommendation No significant changes.
CSS Level 1
The definition of 'border-left' in that specification.
Recommendation Initial definition.

Initial valueas each of the properties of the shorthand:
Applies toall elements. It also applies to ::first-letter.
Inheritedno
Mediavisual
Computed valueas each of the properties of the shorthand:
Animation typeas each of the properties of the shorthand:
Canonical orderorder of appearance in the formal grammar of the values

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support112143.51
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support1 ? Yes4 Yes Yes ?

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最近更新: mfuji09,