下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
| 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_CDATA_SECTION_NODE
(integer)
|
4 | |
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_DOCUMENT_TYPE_NODE
(integer)
|
10 | |
XML_DOCUMENT_FRAG_NODE
(integer)
|
11 | |
XML_NOTATION_NODE
(integer)
|
12 | |
XML_GLOBAL_NAMESPACE
(integer)
|
1 | |
XML_LOCAL_NAMESPACE
(integer)
|
2 | |
XML_HTML_DOCUMENT_NODE
(integer)
|
||
XML_DTD_NODE
(integer)
|
||
XML_ELEMENT_DECL_NODE
(integer)
|
||
XML_ATTRIBUTE_DECL_NODE
(integer)
|
||
XML_ENTITY_DECL_NODE
(integer)
|
||
XML_NAMESPACE_DECL_NODE
(integer)
|
||
XML_ATTRIBUTE_CDATA
(integer)
|
||
XML_ATTRIBUTE_ID
(integer)
|
||
XML_ATTRIBUTE_IDREF
(integer)
|
||
XML_ATTRIBUTE_IDREFS
(integer)
|
||
XML_ATTRIBUTE_ENTITY
(integer)
|
||
XML_ATTRIBUTE_NMTOKEN
(integer)
|
||
XML_ATTRIBUTE_NMTOKENS
(integer)
|
||
XML_ATTRIBUTE_ENUMERATION
(integer)
|
||
XML_ATTRIBUTE_NOTATION
(integer)
|
||
XPATH_UNDEFINED
(integer)
|
||
XPATH_NODESET
(integer)
|
||
XPATH_BOOLEAN
(integer)
|
||
XPATH_NUMBER
(integer)
|
||
XPATH_STRING
(integer)
|
||
XPATH_POINT
(integer)
|
||
XPATH_RANGE
(integer)
|
||
XPATH_LOCATIONSET
(integer)
|
||
XPATH_USERS
(integer)
|