org.w3c.dom.events
Interface EventTarget

All Known Subinterfaces:

ExtendedNode, NodeEventTarget

All Known Implementing Classes:

AbstractElement, AbstractNode

public interface EventTarget

The 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

addEventListener

public 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. 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.

removeEventListener

public void removeEventListener(String type,
                                EventListener listener,
                                boolean useCapture)

This method allows the removal of event listeners from the default group. Calling 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.

dispatchEvent

public boolean dispatchEvent(Event evt)
                      throws EventException,
                             DOMException

This method allows the dispatch of events into the implementation's event model. The event target of the event is the 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] .

addEventListenerNS

public 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.

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

removeEventListenerNS

public 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. Calling 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