operator
key of data-attribute of attribute-reference
The key of data-attribute
operator returns the "true" name of the data-attribute. This is most useful when
retrieving the real name of an data-attribute that is being referenced through an alias. The name is uppercased when
the SGML declaration specifies NAMECASE GENERAL YES
for the SGML document being
processed.
Because data-attributes are always considered part of a shelf of attributes, it always makes sense to ask for
the "key" of a data-attribute, even if the data-attribute
form is used rather than
data-attributes
.