Attr interface represents an attribute in an
* Element object. Typically the allowable values for the
* attribute are defined in a document type definition.
* Attr objects inherit the Node interface, but
* since they are not actually child nodes of the element they describe, the
* DOM does not consider them part of the document tree. Thus, the
* Node attributes parentNode,
* previousSibling, and nextSibling have a
* null value for Attr objects. The DOM takes the
* view that attributes are properties of elements rather than having a
* separate identity from the elements they are associated with; this should
* make it more efficient to implement such features as default attributes
* associated with all elements of a given type. Furthermore,
* Attr nodes may not be immediate children of a
* DocumentFragment. However, they can be associated with
* Element nodes contained within a
* DocumentFragment. In short, users and implementors of the
* DOM need to be aware that Attr nodes have some things in
* common with other objects inheriting the Node interface, but
* they also are quite distinct.
*
The attribute's effective value is determined as follows: if this
* attribute has been explicitly assigned any value, that value is the
* attribute's effective value; otherwise, if there is a declaration for
* this attribute, and that declaration includes a default value, then that
* default value is the attribute's effective value; otherwise, the
* attribute does not exist on this element in the structure model until it
* has been explicitly added. Note that the nodeValue attribute
* on the Attr instance can also be used to retrieve the string
* version of the attribute's value(s).
*
In XML, where the value of an attribute can contain entity references,
* the child nodes of the Attr node may be either
* Text or EntityReference nodes (when these are
* in use; see the description of EntityReference for
* discussion). Because the DOM Core is not aware of attribute types, it
* treats all attribute values as simple strings, even if the DTD or schema
* declares them as having tokenized types.
*
See also the Document Object Model (DOM) Level 2 Core Specification.
*/
public interface Attr extends Node {
/**
* Returns the name of this attribute.
*/
public String getName();
/**
* 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 specified is 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
* specified is 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. If
* the ownerElement attribute is null (i.e.
* because it was just created or was set to null by the
* various removal and cloning operations) specified is
* true.
*/
public boolean getSpecified();
/**
* On retrieval, the value of the attribute is returned as a string.
* Character and general entity references are replaced with their
* values. See also the method getAttribute on the
* Element interface.
*
On setting, this creates a Text node with the unparsed
* contents of the string. I.e. any characters that an XML processor
* would recognize as markup are instead treated as literal text. See
* also the method setAttribute on the Element
* interface.
* @exception DOMException
* NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
*/
public String getValue();
public void setValue(String value)
throws DOMException;
/**
* The Element node this attribute is attached to or
* null if this attribute is not in use.
* @since DOM Level 2
*/
public Element getOwnerElement();
}