class Attr

# class Attr | The `Attr` interface represents an attribute in an `Element` object. More...
Full name | `DOM::Attr`
Definition | `#include <dom_element.h>`
Inherits | DOM::Node [public ]
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#### Public Methods

- Attr ()
- Attr (const Node &other)
- Attr (const Attr &other)
- Attr & operator = (const Node &other)
- Attr & operator = (const Attr &other)
- ~Attr ()
- DOMString name () const
- bool specified () const
- DOMString value () const
- void setValue ( const DOMString & )
- Element ownerElement () const

#### Protected Methods

- Attr ( AttrImpl *_impl )

## Detailed Description

The `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 provide a representation in which entity references are not expanded. These child nodes may be either `Text` or `EntityReference` nodes. Because the attribute type may be unknown, there are no tokenized attribute values.

Attr () | ### Attr

Attr (const Node &other) | ### Attr

Attr (const Attr &other) | ### Attr

Attr & operator = (const Node &other) | ### operator =

Reimplemented from Node.

Attr & operator = (const Attr &other) | ### operator =

Reimplemented from Node.

~Attr () | ### ~Attr

DOMString name () | ### name

[const]

Returns the name of this attribute.

bool specified () | ### specified

[const]

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.

DOMString value () | ### value

[const]

On retrieval, the value of the attribute is returned as a string. Character and general entity references are replaced with their values.

On setting, this creates a `Text` node with the unparsed contents of the string.

void setValue ( const DOMString & ) | ### setValue

see value

Element ownerElement () | ### ownerElement

[const]

Introduced in DOM Level 2

The Element node this attribute is attached to or null if this attribute is not in use.

Attr ( AttrImpl *_impl ) | ### Attr

[protected]

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