<when> (when) indicates a point in time either relative to other elements in the same <timeline> tag, or absolutely.
Attributes:
absolute supplies an absolute value for the time.
Datatype: CDATA
Values: Times may be given in standard form, as specified in the Encoding Declarations section of the header.
Default: #IMPLIED
Note

Required for the element designated as the value of the origin attribute in the <timeline> tag.

unit specifies the unit of time corresponding to the interval value.
Datatype: NMTOKEN
Values: a semi-closed list of recognized time units such as ``millisecond'', ``second'', ``minute''
Default: %INHERITED;
interval specifies the numeric portion of a time interval
Datatype: CDATA
Values: -1 or any positive number
Default: %INHERITED;
Note

The value -1 indicates uncertainty about the interval.

since identifies the reference point for determining the time of the current <when> element, which is obtained by adding the interval to the time of the reference point.
Datatype: IDREF
Values: Should point to another <when> element in the same <timeline> .
Default: #IMPLIED
Note

If this attribute is omitted, and the absolute attribute is not specified, then the reference point is understood to be the origin of the enclosing <timeline> tag.

id supplies an identifier, unique to the document, for each <when> element.
Datatype: ID
Values: any valid name
Default: #REQUIRED
Note

Example 
<when id=w3 since=w2 interval=20>
Tagsetadditional tag set for
Class
Filenameteilink2.dtd
Content: empty
Parentstimeline
Children[none]
Declaration
<!ELEMENT when          - O  EMPTY                              >
<!ATTLIST when               %a.analysis
                             %a.linking
                             %a.terminology
          n                  CDATA               #IMPLIED
          lang               IDREF               %INHERITED
                                                  
          rend               CDATA               #IMPLIED
          absolute           CDATA               #IMPLIED
          unit               NMTOKEN             %INHERITED;
          interval           CDATA               %INHERITED;
          since              IDREF               #IMPLIED
          id                 ID                  #REQUIRED      >
See 14.5.2

Back to index