Complex attribute definitions

In this section:

1. The href attribute
2. 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 a global 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.
3. The keyref attribute
   The keyref attribute provides an indirect, late-bound reference to topics, to collections of topics (ditabase), to maps, to referenceable portions of maps, to non-DITA documents, to external URIs, or to XML content contained within a key definition topic reference. When the DITA content is processed, the key references are resolved using key definitions from DITA maps.
4. The conref attribute
   This attribute is used to reference content that can be reused. It allows reuse of DITA elements, including topic or map level elements.
5. The conaction attribute
   The conaction attribute allows users to push content from one topic into another. It causes the conref attribute to work in reverse, so that the content is pushed from the current topic into another, rather than pulled from another topic into the current one.
6. The conrefend attribute
   The conrefend attribute is used when referencing a range of elements with the conref mechanism. The conref or conkeyref attribute points to the first element in the range, while conrefend points to the last element in the range. Although the start and end elements must be of the same type as the referencing element (or specialized from that element), the intermediary, contiguous nodes in the middle of the range do not have to be the same.
7. The conkeyref attribute
   The conkeyref attribute provides an indirect content reference to topic elements, map elements, or elements within maps or topics. When the DITA content is processed, the key references are resolved using key definitions from DITA maps.
8. The type attribute
   The type attribute is most often used on linking elements to describe the target of a cross-reference. It is also used on the note element to describe the type of the current note, and on several other elements for varying purposes.
9. The format attribute
   The format attribute identifies the format of the resource being cross referenced. The processing default for format is dita. If no value is specified, but the attribute is specified on an ancestor within a map or within the related-links section, the value will cascade from the closest ancestor.
10. The scope attribute
    The scope attribute identifies the closeness of the relationship between the current document and the target resource.
11. The role attribute
    The role attribute defines the role the target topic plays in relationship with the current topic. For example, in a parent/child relationship, the role would be "parent" when the target is the parent of the current topic, and "child" when the target is the child of the current topic. This structure could be used to sort and classify links at display time.