背景颜色 | background-color (Backgrounds & Borders)

  CSS 中文开发手册

背景颜色 | background-color (Backgrounds & Borders) - CSS 中文开发手册

CSS属性中的 background-color 会设置元素的背景色, 属性的值为颜色值或关键字"transparent"二者选其一

/* Keyword values */
background-color: red;

/* Hexadecimal value */
background-color: #bbff00;

/* Hexadecimal value with alpha channel */
background-color: #11ffee00; /* 00 - fully transparent */
background-color: #11ffeeff; /* ff - fully opaque */

/* RGB value */
background-color: rgb(255, 255, 128);

/* RGBA value or RGB with alpha channel */
background-color: rgba(117, 190, 218, 0.0); /* 0.0 - fully transparent */
background-color: rgba(117, 190, 218, 0.5); /* 0.5 - semi-transparent */
background-color: rgba(117, 190, 218, 1.0); /* 1.0 - fully opaque */
​​​​​​​
/* HSLA value */
background-color: hsla(50, 33%, 25%, 0.75);

/* Special keyword values */
background-color: currentcolor;
background-color: transparent;

/* Global values */
background-color: inherit;
background-color: initial;
background-color: unset;

初始值	transparent
适用元素	all elements. It also applies to ::first-letter and ::first-line.
是否是继承属性	no
适用媒体	visual
计算值	computed color
Animation type	a color
正规顺序	the unique non-ambiguous order defined by the formal grammar

语法

background-color属性被指定为单个<color>值。

值

<color>是<color>描述背景的统一颜色的CSS 。即使background-image定义了一个或几个，如果图像不透明，透明度也会影响渲染效果。在CSS中，transparent是一种颜色。

正式语法

<color>where 
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
where 
<rgb()> = rgb( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<rgba()> = rgba( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<hsl()> = hsl( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )
<hsla()> = hsla( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )
where 
<alpha-value> = <number> | <percentage>
<hue> = <number> | <angle>

示例

HTML

<div class="exampleone">
 Lorem ipsum dolor sit amet, consectetuer
</div>

<div class="exampletwo">
  Lorem ipsum dolor sit amet, consectetuer
</div>

<div class="examplethree">
  Lorem ipsum dolor sit amet, consectetuer
</div>

CSS

.exampleone {
  background-color: teal;
  color: white;
}

.exampletwo {
  background-color: rgb(153,102,153);
  color: rgb(255,255,204);
}

.examplethree {
  background-color: #777799;
  color: #FFFFFF;
}

结果

规范

Specification	Status	Comment
CSS Backgrounds and Borders Module Level 3The definition of 'background-color' in that specification.	Candidate Recommendation	Though technically removing the transparent keyword, this doesn't change anything as it has been incorporated as a true <color>
CSS Level 2 (Revision 1)The definition of 'background-color' in that specification.	Recommendation	No change
CSS Level 1The definition of 'background-color' in that specification.	Recommendation	Initial definition

浏览器兼容性

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic Support	1.0	12	1.0	4.01	3.5	1.0
Alpha channel for hex values	52.0	No	No	No	No	No

Feature	Android	Chrome for Android	Edge mobile	Firefox for Android	IE mobile	Opera Android	iOS Safari
Basic Support	(Yes)	(Yes)	(Yes)	1.0	(Yes)	(Yes)	(Yes)
Alpha channel for hex values	52.0	52.0	No	No	No	No	No

在Internet Explorer 8和9中，存在一个错误，即计算background-color的transparent会使得click事件不会被重叠元素触发

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