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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

<custom-ident> CSS data type denotes an arbitrary user-defined string used as an identifier . It is case-sensitive, and certain values are forbidden in various contexts to prevent ambiguity.

句法

The syntax of <custom-ident> is similar to CSS identifiers (such as property names), except that it is case-sensitive . It consists of one or more characters, where characters can be any of the following:

• any alphabetical character ( A to Z ，或 a to z ),
• any decimal digit ( 0 to 9 ),
• a hyphen ( - ),
• an underscore ( _ ),
• an escaped character (preceded by a backslash, \ ),
• a Unicode character (in the format of a backslash, \ , followed by one to six hexadecimal digits, representing its Unicode code point)

注意， id1 , Id1 , iD1 and ID1 are all different identifiers as they are case-sensitive . On the other hand, as there are several ways to escape a character, toto\? and toto\3F are the same identifiers.

Forbidden values

A <custom-ident> must not be placed between single or double quotes as this would be identical to a <string> . Moreover, the first character must not be a decimal digit, nor a hyphen ( - ) followed by a decimal digit or another hyphen.

To prevent ambiguity, each property that uses <custom-ident> forbids the use of specific values:

animation-name

Forbids the global CSS values ( unset , initial ，和 inherit ), as well as none .

counter-reset

counter-increment

Forbids the global CSS values ( unset , initial ，和 inherit ), as well as none .

@counter-style

list-style-type

Forbids the global CSS values ( unset , initial ，和 inherit ), as well as the values none , inline ，和 outside . Also, quite a few predefined values are implemented by the different browsers: 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 , mongolian , myanmar , oriya , persian , simp-chinese-formal , simp-chinese-informal , tamil , telugu , thai , tibetan , 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

Forbids the span 值。

will-change

Forbids the global CSS values ( unset , initial ，和 inherit ), as well as the values will-change , auto , scroll-position ，和 contents .

范例

Valid identifiers

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
\22 toto          A Unicode character followed by a sequence of alphanumeric characters
bili\.bob         A correctly escaped period
					

Invalid identifiers

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>.
					

规范

规范	状态	注释
CSS Values and Units Module Level 4 The definition of ' <custom-ident> ' in that specification.	编者草案
CSS Will Change Module Level 1 The definition of ' <custom-ident> for will-change ' in that specification.	候选推荐	Defines which values are excluded for will-change .
CSS Counter Styles Level 3 The definition of ' <custom-ident> for list-style-type ' in that specification.	候选推荐	Uses <custom-ident> instead of a finite list of keywords. Defines which values are excluded for list-style-type and @counter-style .
CSS Lists Module Level 3 The definition of ' <custom-ident> for counter-* ' in that specification.	工作草案	Renames <identifier> to <custom-ident> . Adds its usage to the new counter-set 特性。
CSS 动画 The definition of ' <custom-ident> for animation-name ' in that specification.	工作草案	Defines which values are excluded for animation-name .
CSS Values and Units Module Level 3 The definition of ' <custom-ident> ' in that specification.	候选推荐	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.	推荐	初始定义。

浏览器兼容性

As this type is not a real type but a convenience type used to simplify the description of allowed values, there is no browser compatibility information as such.

另请参阅

• <ident>

元数据

• 最后修改： Jun 25, 2020

相关话题

1. CSS
2. CSS 参考
3. CSS Will Change
4. CSS 计数器样式
5. CSS Lists and Counters
6. CSS 动画
7. CSS Types
8. 指南

   1. Consistent list indentation
   2. Using CSS counters
   3. CSS 动画提示和技巧
   4. 检测 CSS 动画支持
   5. 使用 CSS 动画
9. At-Rules

   1. @counter-style
   2. @keyframes
10. 特性

    1. <angle-percentage>
    2. <angle>
    3. <basic-shape>
    4. <blend-mode>
    5. <custom-ident>
    6. <dimension>
    7. <frequency-percentage>
    8. <frequency>
    9. <gradient>
    10. <image>
    11. <integer>
    12. <length-percentage>
    13. <length>
    14. <number>
    15. <percentage>
    16. <ratio>
    17. <resolution>
    18. <shape>
    19. <string>
    20. <time-percentage>
    21. <time>
    22. <transform-function>
    23. <url>
    24. animation
    25. animation-delay
    26. animation-direction
    27. animation-duration
    28. animation-fill-mode
    29. animation-iteration-count
    30. animation-name
    31. animation-play-state
    32. animation-timing-function
    33. color
    34. counter-increment
    35. counter-reset
    36. counter-set
    37. flex
    38. ident
    39. list-style
    40. list-style-image
    41. list-style-position
    42. list-style-type
    43. position
    44. will-change