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public interface EventTarget
The EventTarget
interface is implemented by all
Nodes
in an implementation which supports the DOM Event
Model. Therefore, this interface can be obtained by using
binding-specific casting methods on an instance of the Node
interface. The interface allows registration and removal of
EventListeners
on an EventTarget
and dispatch
of events to that EventTarget
.
See also the Document Object Model (DOM) Level 2 Events Specification.
Method Summary | |
---|---|
void |
addEventListener(java.lang.String type,
EventListener listener,
boolean useCapture)
This method allows the registration of event listeners on the event target. |
boolean |
dispatchEvent(Event evt)
This method allows the dispatch of events into the implementations event model. |
void |
removeEventListener(java.lang.String type,
EventListener listener,
boolean useCapture)
This method allows the removal of event listeners from the event target. |
Method Detail |
---|
void addEventListener(java.lang.String type, EventListener listener, boolean useCapture)
EventListener
is added to an
EventTarget
while it is processing an event, it will not
be triggered by the current actions but may be triggered during a
later stage of event flow, such as the bubbling phase.
EventListener
s are registered
on the same EventTarget
with the same parameters the
duplicate instances are discarded. They do not cause the
EventListener
to be called twice and since they are
discarded they do not need to be removed with the
removeEventListener
method.
type
- The event type for which the user is registeringlistener
- The listener
parameter takes an interface
implemented by the user which contains the methods to be called
when the event occurs.useCapture
- If true, useCapture
indicates that the
user wishes to initiate capture. After initiating capture, all
events of the specified type will be dispatched to the registered
EventListener
before being dispatched to any
EventTargets
beneath them in the tree. Events which
are bubbling upward through the tree will not trigger an
EventListener
designated to use capture.void removeEventListener(java.lang.String type, EventListener listener, boolean useCapture)
EventListener
is removed from an
EventTarget
while it is processing an event, it will not
be triggered by the current actions. EventListener
s can
never be invoked after being removed.
removeEventListener
with arguments which do
not identify any currently registered EventListener
on
the EventTarget
has no effect.
type
- Specifies the event type of the EventListener
being removed.listener
- The EventListener
parameter indicates the
EventListener
to be removed.useCapture
- Specifies whether the EventListener
being removed was registered as a capturing listener or not. If a
listener was registered twice, one with capture and one without,
each must be removed separately. Removal of a capturing listener
does not affect a non-capturing version of the same listener, and
vice versa.boolean dispatchEvent(Event evt) throws EventException
EventTarget
on which dispatchEvent
is
called.
evt
- Specifies the event type, behavior, and contextual
information to be used in processing the event.
dispatchEvent
indicates
whether any of the listeners which handled the event called
preventDefault
. If preventDefault
was
called the value is false, else the value is true.
EventException
- UNSPECIFIED_EVENT_TYPE_ERR: Raised if the Event
's type
was not specified by initializing the event before
dispatchEvent
was called. Specification of the
Event
's type as null
or an empty string
will also trigger this exception.
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