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.
Inherited Constant Summary
Public Method Summary
abstract String | |
abstract String |
getAttributeNS(String namespaceURI, String localName)
Retrieves an attribute value by local name and namespace URI.
|
abstract Attr | |
abstract Attr |
getAttributeNodeNS(String namespaceURI, String localName)
Retrieves an
Attr node by local name and namespace URI. |
abstract NodeList |
getElementsByTagName(String name)
Returns a
NodeList of all descendant Elements
with a given tag name, in document order. |
abstract 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. |
abstract TypeInfo |
getSchemaTypeInfo()
The type information associated with this element.
|
abstract String |
getTagName()
The name of the element.
|
abstract 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. |
abstract 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. |
abstract void | |
abstract void |
removeAttributeNS(String namespaceURI, String localName)
Removes an attribute by local name and namespace URI.
|
abstract Attr | |
abstract void | |
abstract void | |
abstract Attr | |
abstract Attr | |
abstract 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
. |
abstract 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
. |
abstract 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
. |
Inherited Method Summary
Public Methods
public abstract String getAttribute (String name)
Retrieves an attribute value by name.
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.
public abstract String getAttributeNS (String namespaceURI, String localName)
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.
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]). |
---|
public abstract 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.
Parameters
name | The name (nodeName ) of the attribute to
retrieve. |
---|
Returns
- The
Attr
node with the specified name (nodeName
) ornull
if there is no such attribute.
public abstract Attr getAttributeNodeNS (String namespaceURI, String localName)
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.
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 ornull
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]). |
---|
public abstract NodeList getElementsByTagName (String name)
Returns a 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.
public abstract 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.
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 matchedElements
.
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]). |
---|
public abstract 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.
public abstract 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.
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.
public abstract 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.
Per [XML Namespaces]
, applications must use the value 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]). |
---|
public abstract void removeAttribute (String name)
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.
Parameters
name | The name of the attribute to remove. |
---|
Throws
DOMException | NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. |
---|
public abstract void removeAttributeNS (String namespaceURI, String localName)
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.
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]). |
---|
public abstract Attr removeAttributeNode (Attr oldAttr)
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.
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.
|
---|
public abstract void setAttribute (String name, String value)
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.
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. |
---|
public abstract void setAttributeNS (String namespaceURI, String qualifiedName, String value)
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.
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]). |
---|
public abstract Attr setAttributeNode (Attr newAttr)
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.
Parameters
newAttr | The Attr node to add to the attribute list. |
---|
Returns
- If the
newAttr
attribute replaces an existing attribute, the replacedAttr
node is returned, otherwisenull
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.
|
---|
public abstract Attr setAttributeNodeNS (Attr newAttr)
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.
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 replacedAttr
node is returned, otherwisenull
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]). |
---|
public abstract 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
. 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.
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. |
---|
public abstract 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
. 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. |
---|
public abstract 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
. 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. |
---|