label for=id Binding Check
Resolves explicit label for binding from document-order IDs and labelability flags. An explicit for attribute uses the first matching ID; a nonlabelable first match prevents binding to a later duplicate.
Description
An explicit label for attribute binds through an element ID.
An explicit label for attribute binds through an element ID. Duplicate IDs can break the expected association when the first match is not labelable.1
Resolves explicit label for binding from document-order IDs and labelability flags. An explicit for attribute uses the first matching ID; a nonlabelable first match prevents binding to a later duplicate.
When to use label for=id Binding Check
Use this for the following task: Resolves explicit label for binding from document-order IDs and labelability flags. An explicit for attribute uses the first matching ID; a nonlabelable first match prevents binding to a later duplicate.
Prepare the parsed attribute values, element states or ordered local lists requested below. Keep attribute presence separate from value.
How to use label for=id Binding Check and understand its results
- Prepare the parsed attribute values, element states or ordered local lists requested below. Keep attribute presence separate from value.
- Enter hasFor, forId, elementIds, labelable, implicitLabelableCount using the field table, then run the tool.
- Read bound, targetIndex, duplicateId. Interpret flags, units, ordering and placeholder values using the rules below.
- Review any reported issue or failed check, correct the supplied values when appropriate, and verify the result in its intended context.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| hasFor | Has For | boolean | Required |
| forId | For Id | string; maximum text length 100000 | Required |
| elementIds | Element Ids | list of string; minimum entries 0; maximum entries 10000; each entry: string; maximum text length 10000 | Required |
| labelable | Labelable | list of boolean; minimum entries 0; maximum entries 10000; each entry: boolean | Required |
| implicitLabelableCount | Implicit Labelable Count | integer; minimum 0; maximum 10000 | Required |
Supply element IDs and labelability in document order. Explicit for uses only the first match; an explicit empty for does not bind. Without for, the supplied positive implicit-labelable count establishes binding.2
targetIndex = first matching nonempty forId; bound = target is labelable This summarizes the declared operation. Units, indexing, inclusivity and exceptional cases are explained in the surrounding text.
| Output field | Meaning | Value type |
|---|---|---|
| bound | Bound | boolean |
| targetIndex | Target Index | integer |
| duplicateId | Duplicate Id | boolean |
{
"input": {
"hasFor": true,
"forId": "email",
"elementIds": [
"email",
"email"
],
"labelable": [
false,
true
],
"implicitLabelableCount": 0
},
"output": {
"bound": false,
"targetIndex": 0,
"duplicateId": true
}
}Limitations and assumptions
Indices are zero based and −1 means no explicit target. This does not discover implicit descendants or validate duplicate-ID conformance.
This evaluates supplied local information; it does not fetch a page or run a browser. Malformed requests produce input errors. A successfully evaluated request can still contain false flags, empty result lists or a result outside the supplied threshold; those outcomes have the meanings stated above.
Alternative or Complementary methods
Choose img alt Presence Checker for this operation: Checks whether a parsed img has an alt attribute and whether its value is empty. Empty alternative text can be appropriate for decorative images; this is a presence check only. For a complementary task, use required/readonly/disabled Diff Table for this operation: Resolves required, readonly and disabled flags for an ordinary input type. Effective disabled includes inherited fieldset state supplied by the caller. Submission eligibility concerns disabling only; name, checkedness and submitter selection are separate.
Further background: HTML / accessibility reference: label for=id Binding Check.
References
Similar or alternative tools
- img alt Presence Checker
Checks whether a parsed img has an alt attribute and whether its value is empty. Empty alternative text can be appropriate for decorative images; this is a presence check only.
- required/readonly/disabled Diff Table
Resolves required, readonly and disabled flags for an ordinary input type. Effective disabled includes inherited fieldset state supplied by the caller. Submission eligibility concerns disabling only; name, checkedness and submitter selection are separate.