Worker
The Worker interface represents a background task 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.
- Value parameters:
- options
An object containing option properties that can be set when creating the object instance.
- scriptURL
A USVString representing the URL of the script the worker will execute. It must obey the same-origin policy.
Value members
Constructors
Concrete methods
The postMessage() method of the Worker interface 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 handled by the structured clone algorithm, which includes cyclical references.
The postMessage() method of the Worker interface 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 handled by the structured clone algorithm, which includes cyclical references.
The Worker can send back information to the thread that spawned it using the DedicatedWorkerGlobalScope.postMessage method.
- Value parameters:
- message
The object to deliver to the worker; this will be in the data field in the event delivered to the DedicatedWorkerGlobalScope.onmessage handler. This may be any value or JavaScript object handled by the structured clone algorithm, which includes cyclical references.
- transfer
An optional array of Transferable objects to transfer ownership of. If the ownership of an object is transferred, it becomes unusable in the context it was sent from and becomes available only to the worker it was sent to. Transferable objects are instances of classes like ArrayBuffer, MessagePort or ImageBitmap objects that can be transferred. null is not an acceptable value for transfer.
The Worker.terminate() method immediately terminates the Worker. This does not offer the worker an opportunity to finish its operations; it is simply stopped at once.
The Worker.terminate() method immediately terminates the Worker. This does not offer the worker an opportunity to finish its operations; it is simply stopped at once.
Inherited methods
The EventTarget.addEventListener() method registers the specified listener on the EventTarget it's called on. The event target may be an Element in a document, the Document itself, a Window, or any other object that supports events (such as XMLHttpRequest).
The EventTarget.addEventListener() method registers the specified listener on the EventTarget it's called on. The event target may be an Element in a document, the Document itself, a Window, or any other object that supports events (such as XMLHttpRequest).
This implementation accepts a settings object of type EventListenerOptions.
- Inherited from:
- EventTarget
The EventTarget.addEventListener() method registers the specified listener on the EventTarget it's called on. The event target may be an Element in a document, the Document itself, a Window, or any other object that supports events (such as XMLHttpRequest).
The EventTarget.addEventListener() method registers the specified listener on the EventTarget it's called on. The event target may be an Element in a document, the Document itself, a Window, or any other object that supports events (such as XMLHttpRequest).
- Inherited from:
- EventTarget
Dispatches an Event at the specified EventTarget, invoking the affected EventListeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) apply to events dispatched manually with dispatchEvent().
Dispatches an Event at the specified EventTarget, invoking the affected EventListeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) apply to events dispatched manually with dispatchEvent().
- Inherited from:
- EventTarget
Removes the event listener previously registered with EventTarget.addEventListener.
Removes the event listener previously registered with EventTarget.addEventListener.
This implementation accepts a settings object of type EventListenerOptions.
- Inherited from:
- EventTarget
Removes the event listener previously registered with EventTarget.addEventListener.
Removes the event listener previously registered with EventTarget.addEventListener.
- Inherited from:
- EventTarget
Concrete fields
The Worker.onmessage property represents an EventHandler, that is a function to be called when the message event occurs. These events are of type MessageEvent and will be called when the worker calls its own postMessage() method: it is the way that a Worker has to give back information to the thread that created it.
The Worker.onmessage property represents an EventHandler, that is a function to be called when the message event occurs. These events are of type MessageEvent and will be called when the worker calls its own postMessage() method: it is the way that a Worker has to give back information to the thread that created it.
Inherited fields
The AbstractWorker.onerror property represents an EventHandler, that is a function to be called when the error event occurs and bubbles through the Worker.
The AbstractWorker.onerror property represents an EventHandler, that is a function to be called when the error event occurs and bubbles through the Worker.
- Inherited from:
- AbstractWorker