Please note, this is a STATIC archive of website developer.mozilla.org from 03 Nov 2016, cach3.com does not collect or store any user information, there is no "phishing" involved.

我們的志工尚未將此文章翻譯為 正體中文 (繁體) 版本。加入我們,幫忙翻譯!

Summary

The background CSS property is a shorthand for setting the individual background values in a single place in the style sheet. background can be used to set the values for one or more of: background-clip, background-color, background-image, background-origin, background-position, background-repeat, background-size, and background-attachment.

The background CSS shorthand property assigns explicit given values and sets missing properties to their initial values.

Initial valueas each of the properties of the shorthand:
Applies toall elements. It also applies to ::first-letter and ::first-line.
Inheritedno
Percentagesas each of the properties of the shorthand:
  • background-position: refer to the size of the background positioning area minus size of background image; size refers to the width for horizontal offsets and to the height for vertical offsets
  • background-size: relative to the background positioning area
Mediavisual
Computed valueas each of the properties of the shorthand:
  • background-image: as specified, but with URIs made absolute
  • background-position: a list, each item consisting of two keywords representing the origin and two offsets from that origin, each given as an absolute length (if given a <length>), otherwise as a percentage
  • background-size: as specified, but with relative lengths converted into absolute lengths
  • background-repeat: a list, each item consisting of two keywords, one per dimension
  • background-origin: as specified
  • background-clip: as specified
  • background-attachment: as specified
  • background-color: If the value is translucent, the computed value will be the rgba() corresponding one. If it isn't, it will be the rgb() corresponding one. The transparent keyword maps to rgba(0,0,0,0).
Animation typeas each of the properties of the shorthand:
Canonical orderorder of appearance in the formal grammar of the values

Syntax

/* Using a <background-color> */
background: green;

/* Using a <bg-image> and <repeat-style> */
background: url("test.jpg") repeat-y;

/* Using a <box> and <background-color> */
background: border-box red;

/* A single image, centered and scaled */
background: no-repeat center/80% url("../img/image.png");
Note: The background-color can only be defined on the last background, as there is only one background color for the whole element.

Values

One or more of the following, in any order:

<attachment>
See background-attachment
<box>
See background-clip
<background-color>
See background-color
<bg-image>
See background-image
<position>
See background-position
<repeat-style>
See background-repeat
<bg-size>
See background-size. This property must be specified after <position>, separated with the '/' character.

Formal syntax

[ <bg-layer> , ]* <final-bg-layer>

where
<bg-layer> = <bg-image> || <position> [ / <bg-size> ]? || <repeat-style> || <attachment> || <box>{1,2}
<final-bg-layer> = <bg-image> || <position> [ / <bg-size> ]? || <repeat-style> || <attachment> || <box> || <box> || <'background-color'>

where
<bg-image> = none | <image>
<position> = [[ left | center | right | top | bottom | <length-percentage> ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] | [ center | [ left | right ] <length-percentage>? ] && [ center | [ top | bottom ] <length-percentage>? ]]
<bg-size> = [ <length-percentage> | auto ]{1,2} | cover | contain
<repeat-style> = repeat-x | repeat-y | [ repeat | space | round | no-repeat ]{1,2}
<attachment> = scroll | fixed | local
<box> = border-box | padding-box | content-box

where
<image> = <url> | <image()> | <image-set()> | <element()> | <cross-fade()> | <gradient>
<length-percentage> = <length> | <percentage>

where
<image()> = image( [ [ <image> | <string> ]? , <color>? ]! )
<image-set()> = image-set( <image-set-option># )
<element()> = element( <id-selector> )
<cross-fade()> = cross-fade( <cf-mixing-image> , <cf-final-image>? )
<gradient> = <linear-gradient()> | <repeating-linear-gradient()> | <radial-gradient()> | <repeating-radial-gradient()>

where
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
<image-set-option> = [ <image> | <string> ] <resolution>
<cf-mixing-image> = <percentage>? && <image>
<cf-final-image> = <image> | <color>
<linear-gradient()> = linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )
<repeating-linear-gradient()> = repeating-linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )
<radial-gradient()> = radial-gradient( [ <ending-shape> || <size> ]? [ at <position> ]? , <color-stop-list> )
<repeating-radial-gradient()> = repeating-radial-gradient( [ <ending-shape> || <size> ]? [ at <position> ]? , <color-stop-list> )

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> = <ident>
<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 | WindowText
<side-or-corner> = [ left | right ] || [ top | bottom ]
<color-stop-list> = <color-stop>{2,}
<ending-shape> = circle | ellipse
<size> = closest-side | farthest-side | closest-corner | farthest-corner | <length> | <length-percentage>{2}

where
<rgb-component> = <integer> | <percentage>
<alpha-value> = <number>
<hue> = <number>
<color-stop> = <color> <length-percentage>?

Examples

HTML

<p class="topbanner">
  Starry sky<br/>
  Twinkle twinkle<br/>
  Starry sky
</p>
<p class="warning">Here is a paragraph<p>

CSS

.warning { 
  background: red; 
}

.topbanner { 
  background: url("https://mdn.mozillademos.org/files/11983/starsolid.gif") #00D repeat-y fixed; 
}

Result

Specifications

Specification Status Comment
CSS Backgrounds and Borders Module Level 3
The definition of 'background' in that specification.
Candidate Recommendation The shorthand property has been extended to support multiple backgrounds and the new background-size, background-origin and background-clip properties.
CSS Level 2 (Revision 1)
The definition of 'background' in that specification.
Recommendation No significant changes
CSS Level 1
The definition of 'background' in that specification.
Recommendation Initial definition

Browser compatibility

Feature Firefox (Gecko) Chrome Internet Explorer Opera Safari
Basic support 1.0 (1.7 or earlier) 1.0 4.0 3.5 1.0
Multiple backgrounds 3.6 (1.9.2) 1.0 9.0 10.5 1.3
SVG image as background 4.0 (2.0) 31.0 9.0 21.0 5.1
Support for background-size 18.0 (18.0) 21.0 9.0 21.0 6.1
Support for background-origin and background-clip 22.0 (22.0) 31.0 9.0 21.0 5.1
Feature Firefox Mobile (Gecko) Android IE Phone Opera Mobile Safari Mobile
Basic support 1.0 (1.9.2) 2.1 10.0 5.0 3.2
Multiple backgrounds 1.0 (1.9.2) 2.1 10.0 5.0 3.2
SVG image as background 4.0 (2.0) 3.0 10.0 ? 4.2
Support for background-size 18.0 (18.0) 3.0 10.0 (Yes) 4.0
Support for background-origin and background-clip 22.0 (22.0) 3.0 10.0 No support 4.0

See also