Validates language tags according to BCP 47/RFC 5646 § 2.1, excluding grandfathered tags. A language tag is a
sequence of subtags identifying a natural language, for example en, fr-CA or zh-Hans-CN; case is not
significant, so EN-us is accepted alongside en-US.
Parameters
value: unknown
The value to validate as a language tag
Returns valueisstring
true if value is a well-formed language tag; false otherwise
Checks if a value is a valid language tag.
Validates language tags according to BCP 47/RFC 5646 § 2.1, excluding grandfathered tags. A language tag is a sequence of subtags identifying a natural language, for example
en,fr-CAorzh-Hans-CN; case is not significant, soEN-usis accepted alongsideen-US.