If this attribute was explicitly given a value in the original document, this is
true; otherwise, it is
false. Note that the implementation is in charge of this attribute, not the user. If the user changes the value of the attribute (even if it ends up having the same value as the default value) then the
specified flag is automatically flipped to
true. To re-specify the attribute as the default value from the DTD, the user must delete the attribute. The implementation will then make a new attribute available with
specified set to
false and the default value (if one exists).
In summary: If the attribute has an assigned value in the document then
true, and the value is the assigned value. If the attribute has no assigned value in the document and has a default value in the DTD, then
false, and the value is the default value in the DTD. If the attribute has no assigned value in the document and has a value of IMPLIED in the DTD, then the attribute does not appear in the structure model of the document.