When defining custom counter styles, the negative descriptor lets you alter the representations of negative counter values, by providing a way to specify symbols to be appended or prepended to the counter representation when the value is negative.

句法

/* <symbol> values */
negative: "-";       /* Prepends '-' if value is negative */
negative: "(" ")";   /* Surrounds value by '(' and ')' if it is negative */
					

first <symbol>

This symbol will be prepended to the representation when the counter is negative.

second <symbol>

If present, this symbol will be appended to the representation when the counter is negative.

描述

If the counter value is negative, the symbol provided as value for the descriptor is prepended to the counter representation; and a second symbol if specified, will be appended to the representation. The negative descriptor has effect only if the system value is symbolic , alphabetic , numeric , additive ,或 extends , if the extended counter style itself uses a negative sign. If the negative descriptor is specified for other systems that don't support negative counter values, then the descriptor is ignored.

形式定义

相关 at-rule @counter-style
初始值 "-" hyphen-minus
计算值 如指定

形式句法

<symbol> <symbol>?

where
<symbol> = <string> | <image> | <custom-ident>

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

where
<image()> = image( <image-tags>? [ <image-src>? , <color>? ]! )
<image-set()> = image-set( <image-set-option># )
<element()> = element( <id-selector> )
<paint()> = paint( <ident>, <declaration-value>? )
<cross-fade()> = cross-fade( <cf-mixing-image> , <cf-final-image>? )
<gradient> = <linear-gradient()> | <repeating-linear-gradient()> | <radial-gradient()> | <repeating-radial-gradient()> | <conic-gradient()>

where
<image-tags> = ltr | rtl
<image-src> = <url> | <string>
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
<image-set-option> = [ <image> | <string> ] <resolution>
<id-selector> = <hash-token>
<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> )
<conic-gradient()> = conic-gradient( [ from <angle> ]? [ at <position> ]?, <angular-color-stop-list> )

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>? )
<side-or-corner> = [ left | right ] || [ top | bottom ]
<color-stop-list> = [ <linear-color-stop> [, <linear-color-hint>]? ]# , <linear-color-stop>
<ending-shape> = circle | ellipse
<size> = closest-side | farthest-side | closest-corner | farthest-corner | <length> | <length-percentage>{2}
<position> = [ [ left | center | right ] || [ top | center | bottom ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] ]
<angular-color-stop-list> = [ <angular-color-stop> [, <angular-color-hint>]? ]# , <angular-color-stop>

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

where
<color-stop-length> = <length-percentage>{1,2}
<color-stop-angle> = <angle-percentage>{1,2}
<angle-percentage> = <angle> | <percentage>

范例

Rendering negative counters

HTML

<ul class="list" start="-3">
  <li>One</li>
  <li>Two</li>
  <li>Three</li>
  <li>Four</li>
  <li>Five</li>
</ul>
					

CSS

@counter-style neg {
  system: numeric;
  symbols: "0" "1" "2" "3" "4" "5" "6" "7" "8" "9";
  negative: "(-" ")";
}
.list {
  list-style: neg;
}
					

结果

规范

规范 状态 注释
CSS Counter Styles Level 3
The definition of 'system' in that specification.
候选推荐 初始定义。

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据
Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
negative Chrome 不支持 No Edge 不支持 No Firefox 完整支持 33 IE 不支持 No Opera 不支持 No Safari 不支持 No WebView Android 不支持 No Chrome Android 不支持 No Firefox Android 完整支持 33 Opera Android 不支持 No Safari iOS 不支持 No Samsung Internet Android 不支持 No

图例

完整支持

完整支持

不支持

不支持

另请参阅

元数据

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