IDs used in ARIA and labels must be unique
Compliance Data & Impact
Disabilities Affected
- Blind
- Deafblind
Requirement(s)
WCAG 2.0 (A): MUST
WCAG Success Criteria
4.1.1 Parsing
Section 508 Guidelines
Not specified, or not applicable
Rule Description
The value assigned to an ARIA ID must be unique to prevent the second instance from being overlooked by assistive technology. Put another way; ARIA ID values may not be used more than once in the same document to differentiate each element from another.
Why it Matters
Duplicate ARIA IDs are common validation errors that may break the accessibility of labels, e.g., form fields, table header cells.
Unique ID’s differentiate each element from another and prevent invalid markup, wherein only the first instance gets acted upon by client-side scripting, or where assistive technologies typically only reference the first one accurately.
How to Fix the Problem
Rename any duplicate ARIA ID values.
Duplicate ARIA IDs are common validation errors that may break the accessibility of labels, e.g., form fields, table header cells.
To fix the problem, change an ID value if it is used more than once to be sure each is unique. Unique ID’s differentiate each element from another and prevent invalid markup, wherein only the first instance gets acted upon by client-side scripting, or where assistive technologies typically only reference the first one accurately.
The Algorithm (in simple terms)
Ensures every ARIA ID value is unique