org.w3c.dom
public interface Element extends Node
Element
interface represents an element in an HTML or XML
document. Elements may have attributes associated with them; since the
Element
interface inherits from Node
, the
generic Node
interface attribute attributes
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.
Note: In DOM Level 2, the method normalize
is
inherited from the Node
interface where it was moved.
See also the Document Object Model (DOM) Level 3 Core Specification.
Method Summary | |
---|---|
String | getAttribute(String name)
Retrieves an attribute value by name. |
Attr | getAttributeNode(String name)
Retrieves an attribute node by name.
|
Attr | getAttributeNodeNS(String namespaceURI, String localName)
Retrieves an Attr node by local name and namespace URI.
|
String | getAttributeNS(String namespaceURI, String localName)
Retrieves an attribute value by local name and namespace URI.
|
NodeList | getElementsByTagName(String name)
Returns a NodeList of all descendant Elements
with a given tag name, in document order. |
NodeList | getElementsByTagNameNS(String namespaceURI, String localName)
Returns a NodeList of all the descendant
Elements with a given local name and namespace URI in
document order. |
TypeInfo | getSchemaTypeInfo()
The type information associated with this element. |
String | getTagName()
The name of the element. |
boolean | hasAttribute(String name)
Returns true when an attribute with a given name is
specified on this element or has a default value, false
otherwise. |
boolean | hasAttributeNS(String namespaceURI, String localName)
Returns true when an attribute with a given local name and
namespace URI is specified on this element or has a default value,
false otherwise.
|
void | removeAttribute(String name)
Removes an attribute by name. |
Attr | removeAttributeNode(Attr oldAttr)
Removes the specified attribute node. |
void | removeAttributeNS(String namespaceURI, String localName)
Removes an attribute by local name and namespace URI. |
void | setAttribute(String name, String value)
Adds a new attribute. |
Attr | setAttributeNode(Attr newAttr)
Adds a new attribute node. |
Attr | setAttributeNodeNS(Attr newAttr)
Adds a new attribute. |
void | setAttributeNS(String namespaceURI, String qualifiedName, String value)
Adds a new attribute. |
void | setIdAttribute(String name, boolean isId)
If the parameter isId is true , this method
declares the specified attribute to be a user-determined ID attribute
. |
void | setIdAttributeNode(Attr idAttr, boolean isId)
If the parameter isId is true , this method
declares the specified attribute to be a user-determined ID attribute
. |
void | setIdAttributeNS(String namespaceURI, String localName, boolean isId)
If the parameter isId is true , this method
declares the specified attribute to be a user-determined ID attribute
. |
Parameters: name The name of the attribute to retrieve.
Returns: The Attr
value as a string, or the empty string
if that attribute does not have a specified or default value.
getAttributeNodeNS
method.Parameters: name The name (nodeName
) of the attribute to
retrieve.
Returns: The Attr
node with the specified name (
nodeName
) or null
if there is no such
attribute.
Attr
node by local name and namespace URI.
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.Parameters: namespaceURI The namespace URI of the attribute to retrieve. localName The local name of the attribute to retrieve.
Returns: The Attr
node with the specified attribute local
name and namespace URI or null
if there is no such
attribute.
Throws: DOMException
NOT_SUPPORTED_ERR: May be raised if the implementation does not
support the feature "XML"
and the language exposed
through the Document does not support XML Namespaces (such as [HTML 4.01]).
Since: DOM Level 2
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.Parameters: namespaceURI The namespace URI of the attribute to retrieve. localName The local name of the attribute to retrieve.
Returns: The Attr
value as a string, or the empty string
if that attribute does not have a specified or default value.
Throws: DOMException
NOT_SUPPORTED_ERR: May be raised if the implementation does not
support the feature "XML"
and the language exposed
through the Document does not support XML Namespaces (such as [HTML 4.01]).
Since: DOM Level 2
NodeList
of all descendant Elements
with a given tag name, in document order.Parameters: name The name of the tag to match on. The special value "*" matches all tags.
Returns: A list of matching Element
nodes.
NodeList
of all the descendant
Elements
with a given local name and namespace URI in
document order.Parameters: namespaceURI The namespace URI of the elements to match on. The special value "*" matches all namespaces. localName The local name of the elements to match on. The special value "*" matches all local names.
Returns: A new NodeList
object containing all the matched
Elements
.
Throws: DOMException
NOT_SUPPORTED_ERR: May be raised if the implementation does not
support the feature "XML"
and the language exposed
through the Document does not support XML Namespaces (such as [HTML 4.01]).
Since: DOM Level 2
Since: DOM Level 3
Node.localName
is different
from null
, this attribute is a qualified name. 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. The HTML DOM returns
the tagName
of an HTML element in the canonical
uppercase form, regardless of the case in the source HTML document.true
when an attribute with a given name is
specified on this element or has a default value, false
otherwise.Parameters: name The name of the attribute to look for.
Returns: true
if an attribute with the given name is
specified on this element or has a default value, false
otherwise.
Since: DOM Level 2
true
when an attribute with a given local name and
namespace URI is specified on this element or has a default value,
false
otherwise.
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.Parameters: namespaceURI The namespace URI of the attribute to look for. localName The local name of the attribute to look for.
Returns: true
if an attribute with the given local name
and namespace URI is specified or has a default value on this
element, false
otherwise.
Throws: DOMException
NOT_SUPPORTED_ERR: May be raised if the implementation does not
support the feature "XML"
and the language exposed
through the Document does not support XML Namespaces (such as [HTML 4.01]).
Since: DOM Level 2
Document.normalizeDocument()
to guarantee this
information is up-to-date.
removeAttributeNS
method.Parameters: name The name of the attribute to remove.
Throws: DOMException NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
Attr
node is defined in the DTD, a new node
immediately appears with the default value as well as the
corresponding namespace URI, local name, and prefix when applicable.
The implementation may handle default values from other schemas
similarly but applications should use
Document.normalizeDocument()
to guarantee this
information is up-to-date.Parameters: oldAttr The Attr
node to remove from the attribute
list.
Returns: The Attr
node that was removed.
Throws: DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised if oldAttr
is not an attribute
of the element.
Document.normalizeDocument()
to guarantee this
information is up-to-date.
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.Parameters: namespaceURI The namespace URI of the attribute to remove. localName The local name of the attribute to remove.
Throws: DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_SUPPORTED_ERR: May be raised if the implementation does not
support the feature "XML"
and the language exposed
through the Document does not support XML Namespaces (such as [HTML 4.01]).
Since: DOM Level 2
Attr
node plus any
Text
and EntityReference
nodes, build the
appropriate subtree, and use setAttributeNode
to assign
it as the value of an attribute.
setAttributeNS
method.Parameters: name The name of the attribute to create or alter. value Value to set in string form.
Throws: DOMException
INVALID_CHARACTER_ERR: Raised if the specified name is not an XML
name according to the XML version in use specified in the
Document.xmlVersion
attribute.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
nodeName
) is already present in the element, it is
replaced by the new one. Replacing an attribute node by itself has no
effect.
setAttributeNodeNS
method.Parameters: newAttr The Attr
node to add to the attribute list.
Returns: If the newAttr
attribute replaces an existing
attribute, the replaced Attr
node is returned,
otherwise null
is returned.
Throws: DOMException
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.
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.Parameters: newAttr The Attr
node to add to the attribute list.
Returns: If the newAttr
attribute replaces an existing
attribute with the same local name and namespace URI, the replaced
Attr
node is returned, otherwise null
is
returned.
Throws: DOMException
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.
NOT_SUPPORTED_ERR: May be raised if the implementation does not
support the feature "XML"
and the language exposed
through the Document does not support XML Namespaces (such as [HTML 4.01]).
Since: DOM Level 2
qualifiedName
, and
its value is changed to be 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 setAttributeNodeNS
or
setAttributeNode
to assign it as the value of an
attribute.
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.Parameters: namespaceURI The namespace URI of the attribute to create or alter. qualifiedName The qualified name of the attribute to create or alter. value The value to set in string form.
Throws: DOMException
INVALID_CHARACTER_ERR: Raised if the specified qualified name is not
an XML name according to the XML version in use specified in the
Document.xmlVersion
attribute.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NAMESPACE_ERR: Raised if the qualifiedName
is
malformed per the Namespaces in XML specification, if the
qualifiedName
has a prefix and the
namespaceURI
is null
, if the
qualifiedName
has a prefix that is "xml" and the
namespaceURI
is different from "
http://www.w3.org/XML/1998/namespace", if the qualifiedName
or its prefix is "xmlns" and the
namespaceURI
is different from "http://www.w3.org/2000/xmlns/", or if the namespaceURI
is "http://www.w3.org/2000/xmlns/" and neither the qualifiedName
nor its prefix is "xmlns".
NOT_SUPPORTED_ERR: May be raised if the implementation does not
support the feature "XML"
and the language exposed
through the Document does not support XML Namespaces (such as [HTML 4.01]).
Since: DOM Level 2
isId
is true
, this method
declares the specified attribute to be a user-determined ID attribute
. This affects the value of Attr.isId
and the behavior
of Document.getElementById
, but does not change any
schema that may be in use, in particular this does not affect the
Attr.schemaTypeInfo
of the specified Attr
node. Use the value false
for the parameter
isId
to undeclare an attribute for being a
user-determined ID attribute.
setIdAttributeNS
method.Parameters: name The name of the attribute. isId Whether the attribute is a of type ID.
Throws: DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised if the specified node is not an attribute
of this element.
Since: DOM Level 3
isId
is true
, this method
declares the specified attribute to be a user-determined ID attribute
. This affects the value of Attr.isId
and the behavior
of Document.getElementById
, but does not change any
schema that may be in use, in particular this does not affect the
Attr.schemaTypeInfo
of the specified Attr
node. Use the value false
for the parameter
isId
to undeclare an attribute for being a
user-determined ID attribute.Parameters: idAttr The attribute node. isId Whether the attribute is a of type ID.
Throws: DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised if the specified node is not an attribute
of this element.
Since: DOM Level 3
isId
is true
, this method
declares the specified attribute to be a user-determined ID attribute
. This affects the value of Attr.isId
and the behavior
of Document.getElementById
, but does not change any
schema that may be in use, in particular this does not affect the
Attr.schemaTypeInfo
of the specified Attr
node. Use the value false
for the parameter
isId
to undeclare an attribute for being a
user-determined ID attribute.Parameters: namespaceURI The namespace URI of the attribute. localName The local name of the attribute. isId Whether the attribute is a of type ID.
Throws: DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised if the specified node is not an attribute
of this element.
Since: DOM Level 3