Description
Decode CSS identifier escape sequences to Unicode scalars with replacement for zero/surrogate/out-of-range code points; requires an already isolated identifier token, not full identifier grammar.
CSS combines token syntax, property-specific value rules and layout/cascade processing. These are separate layers: splitting a declaration does not establish that its value is valid, and arithmetic on resolved lengths does not perform browser layout. Each tool here handles an explicit numeric representation or a stated lexical subset.
Decode CSS identifier escape sequences to Unicode scalars with replacement for zero/surrogate/out-of-range code points; requires an already isolated identifier token, not full identifier grammar.
When to use this tool
Use this tool to decode CSS identifier escape sequences to Unicode scalars with replacement for zero/surrogate/out-of-range code points; requires an already isolated identifier token, not full identifier grammar.
How to use the tool and how it works
- Enter token using the input definitions below.
- Run the operation. Resolve malformed-input errors before interpreting the result.
- Read result.decoded. Interpret signs, units, ordering and null values using the rules below.
Scan an isolated token. A backslash plus 1–6 hex digits decodes a scalar, replacing zero, surrogate values and values above U+10FFFF with U+FFFD; consume one optional whitespace terminator, treating CRLF as one. Other escaped non-newline characters become literal characters.1, 2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| token | One isolated numeric or identifier token in the exact supported grammar. | Text, at most 8,192 UTF-16 code units; the stated grammar and narrower limits also apply. |
| Output field | Interpretation |
|---|---|
| result | Object containing the fields below. |
| result.decoded | Identifier text after the stated escape decoding. |
{
"input": {
"token": "a\\62 c"
},
"output": {
"result": {
"decoded": "abc"
}
}
}Limitations and assumptions
- Raw space/control characters, trailing backslash and escaped newline are rejected. This decodes escapes without validating the full CSS identifier grammar.
- Lengths and times must already be resolved to consistent numeric units. Lexical helpers intentionally support smaller grammars than a full browser CSS parser; malformed supported-subset input causes an error.
- Every declared top-level input is required and unknown fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
- Numeric outputs must be finite and within the absolute safe-integer magnitude; exact larger integers use decimal text. Source positions are zero-based UTF-16 offsets and span ends are exclusive unless a different convention is explicitly stated.
Alternative or Complementary methods
Use a full CSS parser or browser style/layout APIs when escape handling, error recovery, computed styles or the full cascade matter. These tools expose focused transformations and audits of supplied data.
References
Similar or alternative tools
- CSS Number Token Sign Normalizer
Remove a leading plus from the supported decimal-number subset while preserving scale and negative-zero spelling; units and leading-dot numbers are rejected.
- CSS Custom Property Name Token Audit
Audit a deliberately restricted ASCII custom-property token grammar -- followed by letters/digits/underscore/dash; not full CSS identifier validation.