用户定义 | custom-ident (Lists & Counters) - CSS 中文开发手册
<custom-ident>CSS数据类型表示作为任意用户定义的字符串的标识符。它是区分大小写的,并且在各种情况下禁止某些值以防止含糊不清。
句法
其语法<custom-ident>与CSS标识符(如属性名称)类似,区别在于区分大小写。A <custom-ident>是一个字符序列,字符可以是:
任何字母字符‘A‘到‘Z‘,或‘a‘到‘z‘,任何十进制数字‘0‘到‘9‘,连字符‘-‘,下划线‘_‘,一个带有反斜杠的转义字符‘\‘,或一个Unicode字符(格式为反斜杠,后面跟着一到六个十六进制数字,表示其Unicode码位)。
第一个字符不能是十进制数字,也不能是破折号(‘-‘),后面跟十进制数字或其他短划线。甲<custom-ident>不能放置单引号或双引号之间,因为这将是相同的<string>。
需要注意的是id1,Id1,iD1和ID1都是不同的标识符,因为它们区分大小写。另一方面,由于有几种逃避角色的方法,toto\?并且toto\3F是相同的标识符。
禁忌值
为了防止歧义,每个属性使用<custom-ident>禁止使用特定值:
animation-name全局禁止CSS值(unset,,initial和inherit),以及none。counter-resetcounter-increment禁止全球CSS值(unset,,initial和inherit),以及none。@counter-stylelist-style-type禁止全局CSS值(unset,initial,和inherit),以及价值观none,inline和outside。此外,相当多的预设值是由不同的浏览器中实现:disc,circle,square,decimal,cjk-decimal,decimal-leading-zero,lower-roman,upper-roman,lower-greek,lower-alpha,lower-latin,upper-alpha,upper-latin,arabic-indic,armenian,bengali,cambodian,cjk-earthly-branch,cjk-heavenly-stem,cjk-ideographic,devanagari,ethiopic-numeric,georgian,gujarati,gurmukhi,hebrew,hiragana,hiragana-iroha,japanese-formal,japanese-informal,kannada,katakana,katakana-iroha,khmer,korean-hangul-formal,korean-hanja-formal,korean-hanja-informal,lao,lower-armenian,malayalam,*n,myanmar,oriya,persian,simp-chinese-formal,simp-chinese-informal,tamil,telugu,thai,*,trad-chinese-formal,trad-chinese-informal,upper-armenian,disclosure-open,和disclosure-close。grid-row-start
grid-row-end
grid-column-start
grid-column-end禁止span价值。will-change禁止全局CSS值(unset,initial,和inherit),以及价值观will-change,auto,scroll-position,和contents。
实例
有效标识符
nono79 A mix of alphanumeric characters and numbers ground-level A mix of alphanumeric characters and a dash -test A dash followed by alphanumeric characters _internal An underscore followed by alphanumeric characters toto A Unicode character followed by a sequence of alphanumeric characters bili\.bob A correctly escaped period
无效标识符
34rem It must not start with a decimal digit. -12rad It must not start with a dash followed by a decimal digit. bili.bob Only alphanumeric characters, _, and - needn‘t be escaped. --toto It must not start with two dashes. This would be a custom property. ‘bilibob‘ This would be a <string>. "bilibob" This would be a <string>.
规格
Specification | Status | Comment |
---|---|---|
CSS Will Change Module Level 1The definition of ‘<custom-ident> for will-change‘ in that specification. | Working Draft | Defines which values are excluded for will-change. |
CSS Counter Styles Level 3The definition of ‘<custom-ident> for list-style-type‘ in that specification. | Candidate Recommendation | Uses <custom-ident> instead of a finite list of keywords. Defines which values are excluded for list-style-type and @counter-style. |
CSS Lists and Counters Module Level 3The definition of ‘<custom-ident> for counter-*‘ in that specification. | Working Draft | Renames <identifier> to <custom-ident>. Adds its usage to the new counter-set property. |
CSS AnimationsThe definition of ‘<custom-ident> for animation-name‘ in that specification. | Working Draft | Defines which values are excluded for animation-name. |
CSS Values and Units Module Level 3The definition of ‘<custom-ident>‘ in that specification. | Candidate Recommendation | Renames <identifier> to <custom-ident>. Makes it a pseudo-type and forbids the use of excluded values. |
CSS Level 2 (Revision 1)The definition of ‘<identifier>‘ in that specification. | Recommendation | Initial definition. |
浏览器兼容性
用户定义 | custom-ident (Lists & Counters) - CSS 中文开发手册 - Break易站