1 =head1 NAME

     2 

     3 XML::DOM::Element - An XML element node in XML::DOM

     4 

     5 =head1 DESCRIPTION

     6 

     7 XML::DOM::Element extends L<XML::DOM::Node>.

     8 

     9 By far the vast majority of objects (apart from text) that authors

    10 encounter when traversing a document are Element nodes. Assume the

    11 following XML document:

    12 

    13      <elementExample id="demo">

    14        <subelement1/>

    15        <subelement2><subsubelement/></subelement2>

    16      </elementExample>

    17 

    18 When represented using DOM, the top node is an Element node for

    19 "elementExample", which contains two child Element nodes, one for

    20 "subelement1" and one for "subelement2". "subelement1" contains no

    21 child nodes.

    22 

    23 Elements may have attributes associated with them; since the Element

    24 interface inherits from Node, the generic Node interface method

    25 getAttributes may be used to retrieve the set of all attributes for an

    26 element. There are methods on the Element interface to retrieve either

    27 an Attr object by name or an attribute value by name. In XML, where an

    28 attribute value may contain entity references, an Attr object should be

    29 retrieved to examine the possibly fairly complex sub-tree representing

    30 the attribute value. On the other hand, in HTML, where all attributes

    31 have simple string values, methods to directly access an attribute

    32 value can safely be used as a convenience.

    33 

    34 =head2 METHODS

    35 

    36 =over 4

    37 

    38 =item getTagName

    39 

    40 The name of the element. For example, in:

    41 

    42                <elementExample id="demo">

    43                        ...

    44                </elementExample>

    45 

    46 tagName has the value "elementExample". Note that this is

    47 case-preserving in XML, as are all of the operations of the

    48 DOM.

    49 

    50 =item getAttribute (name)

    51 

    52 Retrieves an attribute value by name.

    53 

    54 Return Value: The Attr value as a string, or the empty string if that

    55 attribute does not have a specified or default value.

    56 

    57 =item setAttribute (name, value)

    58 

    59 Adds a new attribute. If an attribute with that name is

    60 already present in the element, its value is changed to be

    61 that of the value parameter. This value is a simple string,

    62 it is not parsed as it is being set. So any markup (such as

    63 syntax to be recognized as an entity reference) is treated as

    64 literal text, and needs to be appropriately escaped by the

    65 implementation when it is written out. In order to assign an

    66 attribute value that contains entity references, the user

    67 must create an Attr node plus any Text and EntityReference

    68 nodes, build the appropriate subtree, and use

    69 setAttributeNode to assign it as the value of an attribute.

    70 

    71 

    72 DOMExceptions:

    73 

    74 =over 4

    75 

    76 =item * INVALID_CHARACTER_ERR

    77 

    78 Raised if the specified name contains an invalid character.

    79 

    80 =item * NO_MODIFICATION_ALLOWED_ERR

    81 

    82 Raised if this node is readonly.

    83 

    84 =back

    85 

    86 =item removeAttribute (name)

    87 

    88 Removes an attribute by name. If the removed attribute has a

    89 default value it is immediately replaced.

    90 

    91 DOMExceptions:

    92 

    93 =over 4

    94 

    95 =item * NO_MODIFICATION_ALLOWED_ERR

    96 

    97 Raised if this node is readonly.

    98 

    99 =back

   100 

   101 =item getAttributeNode

   102 

   103 Retrieves an Attr node by name.

   104 

   105 Return Value: The Attr node with the specified attribute name or undef

   106 if there is no such attribute.

   107 

   108 =item setAttributeNode (attr)

   109 

   110 Adds a new attribute. If an attribute with that name is

   111 already present in the element, it is replaced by the new one.

   112 

   113 Return Value: If the newAttr attribute replaces an existing attribute

   114 with the same name, the previously existing Attr node is

   115 returned, otherwise undef is returned.

   116 

   117 DOMExceptions:

   118 

   119 =over 4

   120 

   121 =item * WRONG_DOCUMENT_ERR

   122 

   123 Raised if newAttr was created from a different document than the one that created

   124 the element.

   125 

   126 =item * NO_MODIFICATION_ALLOWED_ERR

   127 

   128 Raised if this node is readonly.

   129 

   130 =item * INUSE_ATTRIBUTE_ERR

   131 

   132 Raised if newAttr is already an attribute of another Element object. The DOM

   133 user must explicitly clone Attr nodes to re-use them in other elements.

   134 

   135 =back

   136 

   137 =item removeAttributeNode (oldAttr)

   138 

   139 Removes the specified attribute. If the removed Attr has a default value it is

   140 immediately replaced. If the Attr already is the default value, nothing happens

   141 and nothing is returned.

   142 

   143 Parameters:

   144  I<oldAttr>  The Attr node to remove from the attribute list. 

   145 

   146 Return Value: The Attr node that was removed.

   147 

   148 DOMExceptions:

   149 

   150 =over 4

   151 

   152 =item * NO_MODIFICATION_ALLOWED_ERR

   153 

   154 Raised if this node is readonly.

   155 

   156 =item * NOT_FOUND_ERR

   157 

   158 Raised if oldAttr is not an attribute of the element.

   159 

   160 =back

   161 

   162 =head2 Additional methods not in the DOM Spec

   163 

   164 =over 4

   165 

   166 =item setTagName (newTagName)

   167 

   168 Sets the tag name of the Element. Note that this method is not portable

   169 between DOM implementations.

   170 

   171 DOMExceptions:

   172 

   173 =over 4

   174 

   175 =item * INVALID_CHARACTER_ERR

   176 

   177 Raised if the specified name contains an invalid character.

   178 

   179 =back

   180 

   181 =item check ($checker)

   182 

   183 Uses the specified L<XML::Checker> to validate the document.

   184 NOTE: an XML::Checker must be supplied. The checker can be created in

   185 different ways, e.g. when parsing a document with XML::DOM::ValParser,

   186 or with XML::DOM::Document::createChecker().

   187 See L<XML::Checker> for more info.

   188 

   189 =back