HTML ID Reference Token Coverage

Audit an explicit HTML ID-reference token list against supplied document IDs, retaining unknown references and repeated tokens; not DOM traversal or an accessibility certification.

Description

Audit an explicit HTML ID-reference token list against supplied document IDs, retaining unknown references and repeated tokens; not DOM traversal or an accessibility certification.

An ID-reference token list can contain missing targets and repeated references. This audit keeps the original token sequence while exposing both conditions.

When to use this tool

Audit an explicit HTML ID-reference token list against supplied document IDs, retaining unknown references and repeated tokens; not DOM traversal or an accessibility certification.

Prepare the supplied references, ids fields for this operation.
Compare the complete example with the representation used by your own input before carrying the result into another step.

How to use the tool and how it works

Enter references, ids. Use the exact text syntax, units and index conventions explained below.
Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
Read result.tokens, result.missing, result.duplicates. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.

Split references on HTML ASCII whitespace, retain repeats, list distinct tokens absent from ids and group duplicate tokens with every zero-based occurrence index.^[1]

Input field	Meaning and representation	Accepted input
references	references.	Text; at most 8,192 UTF-16 code units, subject to the grammar above
ids	ids.	List of strings; at most 128 entries

Output field	Interpretation
result	Object containing the named outputs below.
result.tokens	The tokens list in the ordering and representation described above.
result.missing	The missing list in the ordering and representation described above.
result.duplicates	The duplicates list in the ordering and representation described above.

json

{
  "input": {
    "references": "a b a",
    "ids": [
      "a"
    ]
  },
  "output": {
    "result": {
      "tokens": [
        "a",
        "b",
        "a"
      ],
      "missing": [
        "b"
      ],
      "duplicates": [
        {
          "key": "a",
          "indexes": [
            0,
            2
          ]
        }
      ]
    }
  }
}

Limitations and assumptions

The tool does not traverse a document or determine which element an ID reference resolves to. Exact case-sensitive text equality defines a match.
All declared input fields are required and unexpected top-level fields are rejected. Numbers must be finite; lists are limited to 128 entries and ordinary text fields to 8,192 UTF-16 code units, with tighter limits where stated.
JSON text inputs must parse within bounded nesting and size limits. Numeric outputs outside the safe finite range are rejected; large exact integer results use decimal strings. Indexes and half-open spans are zero-based unless a rank is explicitly described as one-based.

Alternative or Complementary methods

For actual document behavior, inspect a parsed DOM and the relevant HTML algorithm. These tools transform supplied tokens, observations or coordinates; compare the browser result when parsing or layout matters.

References

Tool behavior and example: HTML ID Reference Token Coverage — tool.io

Similar or alternative tools

HTML ID Reference Ambiguity Audit
Inventory all supplied document ID positions matching each explicit ID-reference token and identify ambiguity instead of arbitrarily choosing the first element.
HTML Attribute Token Value Escape
Escape an explicit HTML quoted attribute value for a selected quote character, including ampersand and angle brackets; not a URL, script or style sanitizer.