||Accessibility of web content requires semantic information about widgets, structures,
and behaviors, in order to allow assistive technologies to convey appropriate information
to persons with disabilities. This specification provides an ontology of roles, states,
and properties that define accessible user interface elements and can be used to improve
the accessibility and interoperability of web content and applications. These semantics
are designed to allow an author to properly convey user interface behaviors and structural
information to assistive technologies in document-level markup.