T.J. Mather > XML-DOM-1.44 > XML::DOM::Element

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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.

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