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XXV. DOM XML functions



This extension is EXPERIMENTAL. The behaviour of this extension -- including the names of its functions and anything else documented about this extension -- may change without notice in a future release of PHP. Use this extension at your own risk.

The DOM XML extension has been overhauled in PHP 4.3.0 to better comply with the DOM standard. The extension still contains many old functions, but they should no longer be used. In particular, functions that are not object-oriented should be avoided.

The extension allows you to operate on an XML document with the DOM API. It also provides a function domxml_xmltree() to turn the complete XML document into a tree of PHP objects. Currently, this tree should be considered read-only — you can modify it, but this would not make any sense since DomDocument_dump_mem() cannot be applied to it. Therefore, if you want to read an XML file and write a modified version, use DomDocument_create_element(), DomDocument_create_text_node(), set_attribute(), etc. and finally the DomDocument_dump_mem() function.


This extension makes use of the GNOME XML library. Download and install this library. You will need at least libxml-2.4.14. To use DOM XSLT features you can use the libxslt library and EXSLT enhancements from Download and install these libraries if you plan to use (enhanced> XSLT features. You will need at least libxslt-1.0.18.


This extension is only available if PHP was configured with --with-dom[=DIR]. Add --with-dom-xslt[=DIR] to include DOM XSLT support. DIR is the libxslt install directory. Add --with-dom-exslt[=DIR] to include DOM EXSLT support, where DIR is the libexslt install directory.

Note to Win32 Users: In order to enable this module on a Windows environment, you must copy libxml2.dll from the DLL folder of the PHP/Win32 binary package to the SYSTEM32 folder of your windows machine. (Ex: C:\WINNT\SYSTEM32 or C:\WINDOWS\SYSTEM32)

Deprecated functions

There are quite a few functions that do not fit into the DOM standard and should no longer be used. These functions are listed in the following table. The function DomNode_append_child() has changed its behaviour. It now adds a child and not a sibling. If this breaks your application, use the non-DOM function DomNode_append_sibling().

Table 1. Deprecated functions and their replacements

Old function New function
xmldoc domxml_open_mem()
xmldocfile domxml_open_file()
domxml_new_xmldoc domxml_new_doc()
domxml_dump_mem DomDocument_dump_mem()
domxml_dump_mem_file DomDocument_dump_file()
DomDocument_dump_mem_file DomDocument_dump_file()
DomDocument_add_root DomDocument_create_element() followed by DomNode_append_child()
DomDocument_dtd DomDocument_doctype()
DomDocument_root DomDocument_document_element()
DomDocument_children DomNode_child_nodes()
DomDocument_imported_node No replacement.
DomNode_add_child Create a new node with e.g. DomDocument_create_element() und add it with DomNode_append_child().
DomNode_children DomNode_child_nodes()
DomNode_parent DomNode_parent_node()
DomNode_new_child Create a new node with e.g. DomDocument_create_element() and add it with DomNode_append_child().
DomNode_set_content Create a new node with e.g. DomDocument_create_text_node() and add it with DomNode_append_child().
DomNode_get_content Content is just a text node and can be accessed with DomNode_child_nodes().
DomNode_set_content Content is just a text node and can be added with DomNode_append_child().

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

Table 2. XML constants

Constant Value Description
XML_ELEMENT_NODE (integer) 1 Node is an element
XML_ATTRIBUTE_NODE (integer) 2 Node is an attribute
XML_TEXT_NODE (integer) 3 Node is a piece of text
XML_ENTITY_REF_NODE (integer) 5  
XML_ENTITY_NODE (integer) 6 Node is an entity like  
XML_PI_NODE (integer) 7 Node is a processing instruction
XML_COMMENT_NODE (integer) 8 Node is a comment
XML_DOCUMENT_NODE (integer) 9 Node is a document
XML_NOTATION_NODE (integer) 12  
XML_DTD_NODE (integer)    
XML_ENTITY_DECL_NODE (integer)    
XML_ATTRIBUTE_ID (integer)    
XPATH_UNDEFINED (integer)    
XPATH_NODESET (integer)    
XPATH_BOOLEAN (integer)    
XPATH_NUMBER (integer)    
XPATH_STRING (integer)    
XPATH_POINT (integer)    
XPATH_RANGE (integer)    
XPATH_USERS (integer)    
XPATH_NUMBER (integer)    


The API of the module follows the DOM Level 2 standard as closely as possible. Consequently, the API is fully object-oriented. It is a good idea to have the DOM standard available when using this module. Though the API is object-oriented, there are many functions which can be called in a non-object-oriented way by passing the object to operate on as the first argument. These functions are mainly to retain compatibilty to older versions of the extension, and should not be used when creating new scripts.

This API differs from the official DOM API in two ways. First, all class attributes are implemented as functions with the same name. Secondly, the function names follow the PHP naming convention. This means that a DOM function lastChild() will be written as last_child().

This module defines a number of classes, which are listed — including their method — in the following tables. Classes with an equivalent in the DOM standard are named DOMxxx.

Table 3. List of classes

Class name Parent classes
DomAttribute DomNode
DomCData DomNode
DomComment DomCData : DomNode
DomDocument DomNode
DomDocumentType DomNode
DomElement DomNode
DomEntity DomNode
DomEntityReference DomNode
DomProcessingInstruction DomNode
DomText DomCData : DomNode
Parser Currently still called DomParser

Table 4. DomDocument class (DomDocument : DomNode)

Method name Function name Remark
doctype DomDocument_doctype()  
document_elemnent DomDocument_document_element()  
create_element DomDocument_create_element()  
create_text_node DomDocument_create_text_node()  
create_comment DomDocument_create_comment()  
create_cdata_section DomDocument_create_cdata_section()  
create_processing_instruction DomDocument_create_processing_instruction()  
create_attribute DomDocument_create_attribute()  
create_entity_reference DomDocument_create_entity_reference()  
get_elements_by_tagname DomDocument_get_elements_by_tagname()  
get_element_by_id DomDocument_get_element_by_id()  
dump_mem DomDocument_dump_mem() not DOM standard
dump_file DomDocument_dump_file() not DOM standard
html_dump_mem DomDocument_html_dump_mem() not DOM standard
xpath_init xpath_init not DOM standard
xpath_new_context xpath_new_context not DOM standard
xptr_new_context xptr_new_context not DOM standard

Table 5. DomElement class (DomElement : DomNode)

Method name Function name Remark
tagname DomElement_tagname()  
get_attribute DomElement_get_attribute()  
set_attribute DomElement_set_attribute()  
remove_attribute DomElement_remove_attribute()  
get_attribute_node DomElement_get_attribute_node()  
get_elements_by_tagname DomElement_get_elements_by_tagname()  
has_attribute DomElement_has_attribute()  

Table 6. DomNode class

Method name Remark
DomNode_append_sibling() Not in DOM standard. This function emulates the former behaviour of DomNode_append_child().
DomNode_unlink_node() Not in DOM standard
DomNode_replace_node() Not in DOM standard
DomNode_set_content() Not in DOM standard, deprecated
DomNode_get_content() Not in DOM standard, deprecated
DomNode_dump_node() Not in DOM standard
DomNode_is_blank_node() Not in DOM standard

Table 7. DomAttribute class (DomAttribute : DomNode)

Method name   Remark
name DomAttribute_name()  
value DomAttribute_value()  
specified DomAttribute_specified()  

Table 8. DomProcessingInstruction class (DomProcessingInstruction : DomNode)

Method name Function name Remark
target DomProcessingInstruction_target()  
data DomProcessingInstruction_data()  

Table 9. Parser class

Method name Function name Remark
add_chunk Parser_add_chunk()  
end Parser_end()  

Table 10. XPathContext class

Method name Function name Remark
eval XPathContext_eval()  
eval_expression XPathContext_eval_expression()  
register_ns XPathContext_register_ns()  

Table 11. DomDocumentType class (DomDocumentType : DomNode)

Method name Function name Remark
name DomDocumentType_name()  
entities DomDocumentType_entities()  
notations DomDocumentType_notations()  
public_id DomDocumentType_public_id()  
system_id DomDocumentType_system_id()  
internal_subset DomDocumentType_internal_subset()  

The classes DomDtd is derived from DomNode. DomComment is derived from DomCData.


Many examples in this reference require an XML string. Instead of repeating this string in every example, it will be put into a file which will be included by each example. This include file is shown in the following example section. Alternatively, you could create an XML document and read it with DomDocument_open_file().

Example 1. Include file with XML string

$xmlstr = "<?xml version='1.0' standalone='yes'?>
<!DOCTYPE chapter SYSTEM '/share/sgml/Norman_Walsh/db3xml10/db3xml10.dtd'
[ <!ENTITY sp \"spanish\">
<!-- lsfj  -->
<chapter language='en'><title language='en'>Title</title>
 <para language='ge'>
  <!-- comment -->
  <informaltable ID='findme' language='&amp;sp;'>
   <tgroup cols='3'>

Table of Contents
DomAttribute->name --  Returns name of attribute
DomAttribute->specified --  Checks if attribute is specified
DomAttribute->value --  Returns value of attribute
DomDocument->add_root [deprecated] --  Adds a root node
DomDocument->create_attribute -- Create new attribute
DomDocument->create_cdata_section -- Create new cdata node
DomDocument->create_comment -- Create new comment node
DomDocument->create_element_ns --  Create new element node with an associated namespace
DomDocument->create_element -- Create new element node
DomDocument->create_entity_reference -- 
DomDocument->create_processing_instruction -- Creates new PI node
DomDocument->create_text_node -- Create new text node
DomDocument->doctype --  Returns the document type
DomDocument->document_element --  Returns root element node
DomDocument->dump_file --  Dumps the internal XML tree back into a file
DomDocument->dump_mem --  Dumps the internal XML tree back into a string
DomDocument->get_element_by_id --  Searches for an element with a certain id
DomDocument->get_elements_by_tagname -- 
DomDocument->html_dump_mem --  Dumps the internal XML tree back into a string as HTML
DomDocument->xinclude --  Substitutes XIncludes in a DomDocument Object.
DomDocumentType->entities --  Returns list of entities
DomDocumentType->internal_subset --  Returns internal subset
DomDocumentType->name --  Returns name of document type
DomDocumentType->notations --  Returns list of notations
DomDocumentType->public_id --  Returns public id of document type
DomDocumentType->system_id --  Returns system id of document type
DomElement->get_attribute_node --  Returns value of attribute
DomElement->get_attribute --  Returns value of attribute
DomElement->get_elements_by_tagname --  Gets elements by tagname
DomElement->has_attribute --  Checks to see if attribute exists
DomElement->remove_attribute --  Removes attribute
DomElement->set_attribute --  Adds new attribute
DomElement->tagname --  Returns name of element
DomNode->add_namespace --  Adds a namespace declaration to a node.
DomNode->append_child --  Adds new child at the end of the children
DomNode->append_sibling --  Adds new sibling to a node
DomNode->attributes --  Returns list of attributes
DomNode->child_nodes --  Returns children of node
DomNode->clone_node --  Clones a node
DomNode->dump_node --  Dumps a single node
DomNode->first_child --  Returns first child of node
DomNode->get_content --  Gets content of node
DomNode->has_attributess --  Checks if node has attributes
DomNode->has_child_nodes --  Checks if node has children
DomNode->insert_before --  Inserts new node as child
DomNode->is_blank_node --  Checks if node is blank
DomNode->last_child --  Returns last child of node
DomNode->next_sibling --  Returns the next sibling of node
DomNode->node_name --  Returns name of node
DomNode->node_type --  Returns type of node
DomNode->node_value --  Returns value of a node
DomNode->owner_document --  Returns the document this node belongs to
DomNode->parent_node --  Returns the parent of the node
DomNode->prefix --  Returns name space prefix of node
DomNode->previous_sibling --  Returns the previous sibling of node
DomNode->remove_child --  Removes child from list of children
DomNode->replace_child --  Replaces a child
DomNode->replace_node --  Replaces node
DomNode->set_content --  Sets content of node
DomNode->set_name --  Sets name of node
DomNode->set_namespace --  Sets namespace of a node.
DomNode->unlink_node --  Deletes node
DomProcessingInstruction->data --  Returns data of pi node
DomProcessingInstruction->target --  Returns target of pi node
DomXsltStylesheet->process --  Applies the XSLT-Transformation on a DomDocument Object.
DomXsltStylesheet->result_dump_file --  Dumps the result from a XSLT-Transformation into a file
DomXsltStylesheet->result_dump_mem --  Dumps the result from a XSLT-Transformation back into a string
domxml_new_doc --  Creates new empty XML document
domxml_open_file -- Creates a DOM object from XML file
domxml_open_mem -- Creates a DOM object of an XML document
domxml_version --  Get XML library version
domxml_xmltree --  Creates a tree of PHP objects from an XML document
domxml_xslt_stylesheet_doc --  Creates a DomXsltStylesheet Object from a DomDocument Object.
domxml_xslt_stylesheet_file --  Creates a DomXsltStylesheet Object from a xsl document in a file.
domxml_xslt_stylesheet --  Creates a DomXsltStylesheet Object from a xml document in a string.
xpath_eval_expression --  Evaluates the XPath Location Path in the given string
xpath_eval --  Evaluates the XPath Location Path in the given string
xpath_new_context --  Creates new xpath context
xptr_eval --  Evaluate the XPtr Location Path in the given string
xptr_new_context --  Create new XPath Context