The param (parameter) element specifies a set of values that might be required by an object at runtime. Any number of param elements might appear in the content of an object in any order, but must be placed at the start of the content of the enclosing object. This element is comparable to the XHMTL param element, and its attributes' semantics derive from their HTML definitions. For example, the type attribute differs from the type attribute on many other DITA elements.
See appendix for information about this element in OASIS document type shells.
The following attributes are available on this element: Universal attribute group and the attributes defined below.
- name (REQUIRED)
- The name of the parameter.
- Specifies the value of a run-time parameter that is specified by the name attribute.
- Specifies the type of the value attribute. Allowed values are:
- A value of data means that the value will be evaluated and passed to the object's implementation as a string.
- A value of ref indicates that the value of the value attribute is a URL that designates a resource where run-time values are stored. This allows support tools to identify URLs that are given as parameters.
- A value of object indicates that the value of valuetype is an identifier that refers to an object declaration in the document. The identifier must be the value of the ID attribute set for the declared object element.
- See Using the -dita-use-conref-target value for more information.
- This attribute specifies for a user agent the type of values that will be found at the URI
designated by value. Note that this differs from the type
attribute on many other DITA elements.
- When valuetype is set to "ref", this attribute directly specifies the content type of the resource designated by value.
- Otherwise, if type is specified and keyref is specified and resolvable, this attribute specifies the content type of the resource designated by keyref.
- Otherwise, if type is not specified and keyref is specified and is resolvable, the effective type value specified for the key that is named by the keyref attribute is used as the value of the type attribute.
- Key reference to the thing the parameter references. If valuetype is
specified but is not set to "ref", this attribute is ignored. When
valuetype is not specified and keyref is specified,
it implies a setting of valuetype="ref". When keyref
is specified and the effective value of valuetype is "ref":
- When the key specified by keyref is resolvable and has an associated URI, that URI is used as the value of this element (overriding value, if that is specified).
- When the key specified by keyref is resolvable and has no associated resource (only link text), the keyref attribute is considered to be unresolvable for this element. If value is specified, it is used as fallback.
- When the key specified by keyref is not resolvable, the value of the value attribute is used as a fallback target for the param element.