Rule: id must be unique

Rule ID Control 5
Conformance Required
Definition All id attribute values must be unique on the page.
Purpose
  • id attribute values on form control elements can be used as references by label elements. When id attribute values on the page are not unique, form controls may be incorrectly labelled.
  • aria-labelledby and aria-describedby atributes also depend on unique id values for labeling and adding descriptions to form controls.
Conformance Required
WCAG Success Criteria

Success Criterion 4.1.1 Parsing

Other Related Success Criterion:

Rule Category Forms
Rule Scope Element
Techniques
  • If a form control defines an id attribute, ensure that its value is unique on the page.
Information Links