The
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.
getAttribute
public String getAttribute(String name)
Retrieves an attribute value by name.
name
- The name of the attribute to retrieve.
- The
Attr
value as a string, or the empty string
if that attribute does not have a specified or default value.
getAttributeNS
public String getAttributeNS(String namespaceURI,
String localName)
throws DOMException
Retrieves an attribute value by local name and namespace URI.
Per [
XML Namespaces]
, applications must use the value
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.
namespaceURI
- The namespace URI of the attribute to retrieve.localName
- The local name of the attribute to retrieve.
- The
Attr
value as a string, or the empty string
if that attribute does not have a specified or default value.
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]).
- DOM Level 2
getAttributeNode
public Attr getAttributeNode(String name)
Retrieves an attribute node by name.
To retrieve an attribute node by qualified name and namespace URI,
use the getAttributeNodeNS
method.
name
- The name (nodeName
) of the attribute to
retrieve.
- The
Attr
node with the specified name (
nodeName
) or null
if there is no such
attribute.
getAttributeNodeNS
public Attr getAttributeNodeNS(String namespaceURI,
String localName)
throws DOMException
Retrieves an
Attr
node by local name and namespace URI.
Per [
XML Namespaces]
, applications must use the value
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.
namespaceURI
- The namespace URI of the attribute to retrieve.localName
- The local name of the attribute to retrieve.
- The
Attr
node with the specified attribute local
name and namespace URI or null
if there is no such
attribute.
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]).
- DOM Level 2
getElementsByTagName
public NodeList getElementsByTagName(String name)
Returns a NodeList
of all descendant Elements
with a given tag name, in document order.
name
- The name of the tag to match on. The special value "*"
matches all tags.
- A list of matching
Element
nodes.
getElementsByTagNameNS
public NodeList getElementsByTagNameNS(String namespaceURI,
String localName)
throws DOMException
Returns a NodeList
of all the descendant
Elements
with a given local name and namespace URI in
document order.
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.
- A new
NodeList
object containing all the matched
Elements
.
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]).
- DOM Level 2
getSchemaTypeInfo
public TypeInfo getSchemaTypeInfo()
The type information associated with this element.
- DOM Level 3
getTagName
public String getTagName()
The name of the element. If
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.
hasAttribute
public 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.
name
- The name of the attribute to look for.
true
if an attribute with the given name is
specified on this element or has a default value, false
otherwise.
- DOM Level 2
hasAttributeNS
public boolean hasAttributeNS(String namespaceURI,
String localName)
throws DOMException
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.
Per [
XML Namespaces]
, applications must use the value
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.
namespaceURI
- The namespace URI of the attribute to look for.localName
- The local name of the attribute to look for.
true
if an attribute with the given local name
and namespace URI is specified or has a default value on this
element, false
otherwise.
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]).
- DOM Level 2
removeAttribute
public void removeAttribute(String name)
throws DOMException
Removes an attribute by name. If a default value for the removed
attribute is defined in the DTD, a new attribute 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.
If no attribute with this name is found, this method has no effect.
To remove an attribute by local name and namespace URI, use the
removeAttributeNS
method.
name
- The name of the attribute to remove.
DOMException
- NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
removeAttributeNS
public void removeAttributeNS(String namespaceURI,
String localName)
throws DOMException
Removes an attribute by local name and namespace URI. If a default
value for the removed attribute is defined in the DTD, a new
attribute 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.
If no attribute with this local name and namespace URI is found,
this method has no effect.
Per [
XML Namespaces]
, applications must use the value
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.
namespaceURI
- The namespace URI of the attribute to remove.localName
- The local name of the attribute to remove.
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]).
- DOM Level 2
removeAttributeNode
public Attr removeAttributeNode(Attr oldAttr)
throws DOMException
Removes the specified attribute node. If a default value for the
removed 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.
oldAttr
- The Attr
node to remove from the attribute
list.
- The
Attr
node that was removed.
DOMException
- NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised if oldAttr
is not an attribute
of the element.
setAttribute
public void setAttribute(String name,
String value)
throws DOMException
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.
To set an attribute with a qualified name and namespace URI, use
the setAttributeNS
method.
name
- The name of the attribute to create or alter.value
- Value to set in string form.
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.
setAttributeNS
public void setAttributeNS(String namespaceURI,
String qualifiedName,
String value)
throws DOMException
Adds a new attribute. If an attribute with the same local name and
namespace URI is already present on the element, its prefix is
changed to be the prefix part of the
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.
Per [
XML Namespaces]
, applications must use the value
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.
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.
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]).
- DOM Level 2
setAttributeNode
public Attr setAttributeNode(Attr newAttr)
throws DOMException
Adds a new attribute node. If an attribute with that name (
nodeName
) is already present in the element, it is
replaced by the new one. Replacing an attribute node by itself has no
effect.
To add a new attribute node with a qualified name and namespace
URI, use the setAttributeNodeNS
method.
newAttr
- The Attr
node to add to the attribute list.
- If the
newAttr
attribute replaces an existing
attribute, the replaced Attr
node is returned,
otherwise null
is returned.
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.
setAttributeNodeNS
public Attr setAttributeNodeNS(Attr newAttr)
throws DOMException
Adds a new attribute. If an attribute with that local name and that
namespace URI is already present in the element, it is replaced by
the new one. Replacing an attribute node by itself has no effect.
Per [
XML Namespaces]
, applications must use the value
null
as the
namespaceURI
parameter for methods if they wish to have
no namespace.
newAttr
- The Attr
node to add to the attribute list.
- 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.
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]).
- DOM Level 2
setIdAttribute
public void setIdAttribute(String name,
boolean isId)
throws DOMException
If the parameter 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.
To specify an attribute by local name and namespace URI, use the
setIdAttributeNS
method.
name
- The name of the attribute.isId
- Whether the attribute is a of type ID.
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.
- DOM Level 3
setIdAttributeNS
public void setIdAttributeNS(String namespaceURI,
String localName,
boolean isId)
throws DOMException
If the parameter 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.
namespaceURI
- The namespace URI of the attribute.localName
- The local name of the attribute.isId
- Whether the attribute is a of type ID.
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.
- DOM Level 3
setIdAttributeNode
public void setIdAttributeNode(Attr idAttr,
boolean isId)
throws DOMException
If the parameter 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.
idAttr
- The attribute node.isId
- Whether the attribute is a of type ID.
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.
- DOM Level 3