org.w3c.dom.events
public interface EventTarget
EventTarget
interface is implemented by all the objects
which could be event targets in an implementation which supports the .
The interface allows registration and removal of event listeners, and
dispatch of events to an event target.
When used with , this interface is implemented by all target nodes and
target ancestors, i.e. all DOM Nodes
of the tree support
this interface when the implementation conforms to DOM Level 3 Events
and, therefore, this interface can be obtained by using binding-specific
casting methods on an instance of the Node
interface.
Invoking addEventListener
or
addEventListenerNS
repeatedly on the same
EventTarget
with the same values for the parameters
namespaceURI
, type
, listener
, and
useCapture
has no effect. Doing so does not cause the
EventListener
to be called more than once and does not cause
a change in the triggering order. In order to register a listener for a
different event group () the previously registered listener has to be
removed first.
See also the Document Object Model (DOM) Level 3 Events Specification .
Since: DOM Level 2
Method Summary | |
---|---|
void | addEventListener(String type, EventListener listener, boolean useCapture)
This method allows the registration of an event listener in the
default group and, depending on the useCapture
parameter, on the capture phase of the DOM event flow or its target
and bubbling phases. |
void | addEventListenerNS(String namespaceURI, String type, EventListener listener, boolean useCapture, Object evtGroup)
This method allows the registration of an event listener in a
specified group or the default group and, depending on the
useCapture parameter, on the capture phase of the DOM
event flow or its target and bubbling phases. |
boolean | dispatchEvent(Event evt)
This method allows the dispatch of events into the implementation's
event model. |
void | removeEventListener(String type, EventListener listener, boolean useCapture)
This method allows the removal of event listeners from the default
group. |
void | removeEventListenerNS(String namespaceURI, String type, EventListener listener, boolean useCapture)
This method allows the removal of an event listener, independently of
the associated event group. |
useCapture
parameter, on the capture phase of the DOM event flow or its target
and bubbling phases. Invoking this method is equivalent to invoking
addEventListenerNS
with the same values for the
parameters type
, listener
, and
useCapture
, and the value null
for the
parameters namespaceURI
and evtGroup
.Parameters: type Specifies the Event.type
associated with the
event for which the user is registering. listener The listener
parameter takes an object
implemented by the user which implements the
EventListener
interface and contains the method to be
called when the event occurs. useCapture If true, useCapture
indicates that the
user wishes to add the event listener for the capture phase only,
i.e. this event listener will not be triggered during the target
and bubbling phases. If false
, the event listener will
only be triggered during the target and bubbling phases.
useCapture
parameter, on the capture phase of the DOM
event flow or its target and bubbling phases.Parameters: namespaceURI Specifies the Event.namespaceURI
associated with the event for which the user is registering. type Refer to the EventTarget.addEventListener()
method for a description of this parameter. listener Refer to the
EventTarget.addEventListener()
method for a
description of this parameter. useCapture Refer to the
EventTarget.addEventListener()
method for a
description of this parameter. evtGroup The object that represents the event group to
associate with the EventListener
(see also ). Use
null
to attach the event listener to the default
group.
Since: DOM Level 3
EventTarget
object on which dispatchEvent
is called.Parameters: evt The event to be dispatched.
Returns: Indicates whether any of the listeners which handled the
event called Event.preventDefault()
. If
Event.preventDefault()
was called the returned value
is false
, else it is true
.
Throws: EventException
UNSPECIFIED_EVENT_TYPE_ERR: Raised if the Event.type
was not specified by initializing the event before
dispatchEvent
was called. Specification of the
Event.type
as null
or an empty string
will also trigger this exception.
DISPATCH_REQUEST_ERR: Raised if the Event
object is
already being dispatched. DOMException
NOT_SUPPORTED_ERR: Raised if the Event
object has not
been created using DocumentEvent.createEvent()
.
INVALID_CHARACTER_ERR: Raised if Event.type
is not
an NCName as defined in [XML Namespaces 1.1]
.
removeEventListener
with arguments which
do not identify any currently registered EventListener
on the EventTarget
has no effect. The
Event.namespaceURI
for which the user registered the
event listener is implied and is null
.
Note: Event listeners registered for other event groups
than the default group cannot be removed using this method; see
EventTarget.removeEventListenerNS()
for that effect.
Parameters: type Specifies the Event.type
for which the user
registered the event listener. listener The EventListener
to be removed. useCapture Specifies whether the EventListener
being removed was registered for the capture phase or not. If a
listener was registered twice, once for the capture phase and once
for the target and bubbling phases, each must be removed
separately. Removal of an event listener registered for the capture
phase does not affect the same event listener registered for the
target and bubbling phases, and vice versa.
removeEventListenerNS
with arguments which do not identify any currently registered
EventListener
on the EventTarget
has no
effect.Parameters: namespaceURI Specifies the Event.namespaceURI
associated with the event for which the user registered the event
listener. type Refer to the
EventTarget.removeEventListener()
method for a
description of this parameter. listener Refer to the
EventTarget.removeEventListener()
method for a
description of this parameter. useCapture Refer to the
EventTarget.removeEventListener()
method for a
description of this parameter.
Since: DOM Level 3