添加符号 | @counter-style.additive-symbols

@counter-style.additive-symbols

additive-symbols描述符 定义符号，用于值可累积的可数的system的项。 additive-symbols定义累积的的元组（tuples）,每个元组项都包含一个符号和一个非负整数的权重。additive system被用于构造sign-value numbering （符号-值，指数字的值就是是符号加在一起的值）系统，比如罗马数字。

additive-symbols: 3 "0";
additive-symbols: 3 "0", 2 "\2E\20";
additive-symbols: 3 "0", 2 url(symbol.png

当系统描述符是循环，数字，拼音，象征，或固定的时候，使用symbols代替additive-symbols

Related at-rule	@counter-style
初始值	N/A
适用媒体	all
计算值	as specified
正规顺序	order of appearance in the formal grammar of the values

语法

正式语法

[ <integer> && <symbol> ]#where 
<symbol> = <string> | <image> | <ident>
where 
<image> = <url> | <image()> | <image-set()> | <element()> | <cross-fade()> | <gradient>
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( [ [ <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>? ] )
<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}
<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>? ]]

where 
<alpha-value> = <number> | <percentage>
<hue> = <number> | <angle>
<color-stop> = <color> <length-percentage>?
<length-percentage> = <length> | <percentage>

示例

HTML

<ul class="list">
   <li>One</li>
   <li>Two</li>
   <li>Three</li>
   <li>Four</li>
   <li>Five</li>
</ul>

CSS

@counter-style additive-symbols-example {
  system: additive;
  additive-symbols: I 1;
}
.list {
  list-style: additive-symbols-example;
}

结果

规范

Specification	Status	Comment
CSS Counter Styles Level 3The definition of 'additive-symbols' in that specification.	Candidate Recommendation	Initial definition.

浏览器兼容性

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	No support	33 (33)	No support	No support	No support

Feature	Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	No support	33 (33)	No support	No support	No support