elemental.html

Interface Worker

All Superinterfaces:

AbstractWorker, EventTarget

All Known Implementing Classes:

JsWorker

public interface Worker
extends AbstractWorker

Workers are background tasks that can be easily created and can send messages back to their creators. Creating a worker is as simple as calling the Worker() constructor, specifying a script to be run in the worker thread.

Of note is the fact that workers may in turn spawn new workers as long as those workers are hosted within the same origin as the parent page. In addition, workers may use XMLHttpRequest for network I/O, with the exception that the responseXML and channel attributes on XMLHttpRequest always return null.

For a list of global functions available to workers, see Functions available to workers.

Gecko 2.0 note

(Firefox 4 / Thunderbird 3.3 / SeaMonkey 2.1)

If you want to use workers in extensions, and would like to have access to js-ctypes, you should use the ChromeWorker object instead.

See Using web workers for examples and details.

Method Summary

Modifier and Type	Method and Description
EventListener	getOnmessage() An event listener that is called whenever a MessageEvent with type message bubbles through the worker.
void	postMessage(Object message) Sends a message to the worker's inner scope.
void	postMessage(Object message, Indexable messagePorts) Sends a message to the worker's inner scope.
void	setOnmessage(EventListener arg)
void	terminate() Immediately terminates the worker.
void	webkitPostMessage(Object message)
void	webkitPostMessage(Object message, Indexable messagePorts)

Methods inherited from interface elemental.html.AbstractWorker

addEventListener, addEventListener, dispatchEvent, getOnerror, removeEventListener, removeEventListener, setOnerror

Method Detail

getOnmessage

EventListener getOnmessage()

An event listener that is called whenever a MessageEvent with type message bubbles through the worker. The message is stored in the event's data member.

setOnmessage

void setOnmessage(EventListener arg)

postMessage

void postMessage(Object message)

Sends a message to the worker's inner scope. This accepts a single parameter, which is the data to send to the worker. The data may be any value or JavaScript object that does not contain functions or cyclical references (since the object is converted to JSON internally).

Parameters

aMessage


The object to deliver to the worker; this will be in the data field in the event delivered to the onmessage handler. This may be any value or JavaScript object that does not contain functions or cyclical references (since the object is converted to JSON internally).

postMessage

void postMessage(Object message,
                 Indexable messagePorts)

Sends a message to the worker's inner scope. This accepts a single parameter, which is the data to send to the worker. The data may be any value or JavaScript object that does not contain functions or cyclical references (since the object is converted to JSON internally).

Parameters

aMessage


The object to deliver to the worker; this will be in the data field in the event delivered to the onmessage handler. This may be any value or JavaScript object that does not contain functions or cyclical references (since the object is converted to JSON internally).

terminate

void terminate()

Immediately terminates the worker. This does not offer the worker an opportunity to finish its operations; it is simply stopped at once.

void terminate();

webkitPostMessage

void webkitPostMessage(Object message)

webkitPostMessage

void webkitPostMessage(Object message,
                       Indexable messagePorts)