NAME¶
XML::DOM::Element - An XML element node in XML::DOM
DESCRIPTION¶
XML::DOM::Element extends XML::DOM::Node.
By far the vast majority of objects (apart from text) that authors encounter
when traversing a document are Element nodes. Assume the following XML
document:
<elementExample id="demo">
<subelement1/>
<subelement2><subsubelement/></subelement2>
</elementExample>
When represented using DOM, the top node is an Element node for
"elementExample", which contains two child Element nodes, one for
"subelement1" and one for "subelement2".
"subelement1" contains no child nodes.
Elements may have attributes associated with them; since the Element interface
inherits from Node, the generic Node interface method getAttributes may be
used to retrieve the set of all attributes for an element. There are methods
on the Element interface to retrieve either an Attr object by name or an
attribute value by name. In XML, where an attribute value may contain entity
references, an Attr object should be retrieved to examine the possibly fairly
complex sub-tree representing the attribute value. On the other hand, in HTML,
where all attributes have simple string values, methods to directly access an
attribute value can safely be used as a convenience.
METHODS
- getTagName
- The name of the element. For example, in:
<elementExample id="demo">
...
</elementExample>
tagName has the value "elementExample". Note that this is
case-preserving in XML, as are all of the operations of the DOM.
- getAttribute (name)
- Retrieves an attribute value by name.
Return Value: The Attr value as a string, or the empty string if that
attribute does not have a specified or default value.
- setAttribute (name, value)
- Adds a new attribute. If an attribute with that name is already present in
the element, its value is changed to be that of the value parameter. This
value is a simple string, it is not parsed as it is being set. So any
markup (such as syntax to be recognized as an entity reference) is treated
as literal text, and needs to be appropriately escaped by the
implementation when it is written out. In order to assign an attribute
value that contains entity references, the user must create an Attr node
plus any Text and EntityReference nodes, build the appropriate subtree,
and use setAttributeNode to assign it as the value of an attribute.
DOMExceptions:
- * INVALID_CHARACTER_ERR
- Raised if the specified name contains an invalid character.
- * NO_MODIFICATION_ALLOWED_ERR
- Raised if this node is readonly.
- removeAttribute (name)
- Removes an attribute by name. If the removed attribute has a default value
it is immediately replaced.
DOMExceptions:
- * NO_MODIFICATION_ALLOWED_ERR
- Raised if this node is readonly.
- getAttributeNode
- Retrieves an Attr node by name.
Return Value: The Attr node with the specified attribute name or undef if
there is no such attribute.
- setAttributeNode (attr)
- Adds a new attribute. If an attribute with that name is already present in
the element, it is replaced by the new one.
Return Value: If the newAttr attribute replaces an existing attribute with
the same name, the previously existing Attr node is returned, otherwise
undef is returned.
DOMExceptions:
- * WRONG_DOCUMENT_ERR
- Raised if newAttr was created from a different document than the one that
created the element.
- * NO_MODIFICATION_ALLOWED_ERR
- Raised if this node is readonly.
- * INUSE_ATTRIBUTE_ERR
- Raised if newAttr is already an attribute of another Element object. The
DOM user must explicitly clone Attr nodes to re-use them in other
elements.
- removeAttributeNode (oldAttr)
- Removes the specified attribute. If the removed Attr has a default value
it is immediately replaced. If the Attr already is the default value,
nothing happens and nothing is returned.
Parameters:
oldAttr The Attr node to remove from the attribute list.
Return Value: The Attr node that was removed.
DOMExceptions:
- * NO_MODIFICATION_ALLOWED_ERR
- Raised if this node is readonly.
- * NOT_FOUND_ERR
- Raised if oldAttr is not an attribute of the element.
Additional methods not in the DOM Spec
- setTagName (newTagName)
- Sets the tag name of the Element. Note that this method is not portable
between DOM implementations.
DOMExceptions:
- * INVALID_CHARACTER_ERR
- Raised if the specified name contains an invalid character.
- check ($checker)
- Uses the specified XML::Checker to validate the document. NOTE: an
XML::Checker must be supplied. The checker can be created in different
ways, e.g. when parsing a document with XML::DOM::ValParser, or with
XML::DOM::Document::createChecker(). See XML::Checker for more
info.