The @keys attribute
A @keys attribute consists of one or more space-separated keys. Map
authors define keys using a <topicref> or <topicref>
specialization that contains the @keys attribute. Each key definition introduces
an identifier for a resource referenced from a map. Keys resolve to the resources
given as the
@href value on the key definition <topicref> element, to
content contained within the key definition <topicref> element, or
both.
The @keys attribute uses the following syntax:
- The value of the @keys attribute is one or more space-separated key names.
- Key names consist of characters that are legal in a URI. The case of key names is significant.
- The following characters are prohibited in key names: "{", "}", "[", "]", "/", "#", "?", and whitespace characters.
A key cannot resolve to sub-topic elements, although a @keyref attribute can do so by combining a key with a sub-topic element id.