WorkerGlobalScope object

Represents the global scope of the worker.

Syntax


 self

DOM Information

Inheritance Hierarchy

The WorkerGlobalScope does not inherit from any class or interface.

Members

The WorkerGlobalScope object has these types of members:

Events
Methods
Properties

Events

The WorkerGlobalScope object has these events.

Event	Description
error	Returns an error if a worker throws an unhandled exception.
message	Returns a message from the parent thread to the worker thread, or between two MessagePort objects.

Methods

The WorkerGlobalScope object has these methods.

Method	Description
addEventListener	Registers an event handler for the specified event type.
close	Stops a worker when called inside worker code.
dispatchEvent	Sends an event to the current element.
importScripts	Loads and executes one or more scripts into the worker specified by a URL.
msWriteProfilerMark	Writes a profiling event.
postMessage	Sends a message from the worker to the parent thread.
removeEventListener	Removes an event handler that the addEventListener method registered.

Properties

The WorkerGlobalScope object has these properties.

Property	Access type	Description
console	Read-only	Returns the windows console object to use to send messages.
indexedDB	Read-only	Allows access to the Indexed Database API, as implemented by Internet Explorer 10.
location	Read-only	Returns the WorkerLocation object of a worker.
navigator	Read-only	Returns a WorkerNavigator object.
self	Read-only	Contains a reference to the WorkerGlobalScope object.

Remarks

The WorkerGlobalScope object is accessed by using the self or this property and is accessed only inside a worker. A worker has the following functionality within its scope:

It can use the XMLHttpRequest method.
It has a self property, which contains a reference to the worker object.
It can call all global JavaScript core methods.
It has a navigator object, which provides the appName, appVersion, onLine, userAgent, and platform properties but no others.
The location property creates the WorkerLocation object, which contains URL information on the worker's location. This property is similar to the Window.location property, but is read-only.
It supports the worker versions of the setTimeout, setInterval, clearTimeout, and clearInterval methods, which are similar to the methods of the same name for the Window object.
It can load other JavaScript files into the scope of the worker using the importScripts method.

Workers do not have access to the Document Object Model (DOM), nor the window, document, and parent objects.

To terminate a worker thread from inside, use the close method. From the main document, use the terminate method to terminate the worker thread.

You can send messages to the main document using postMessage and receive messages from the main document using the onmessage message handler.

You can create new child workers from inside a worker. They must all run in the same host and their location depends on the parent worker of the new worker, not the original webpage. Because a new worker is likely to be in a separate process, you shouldn't create too many workers at once. Also, because messages between workers and their parents are copies and not shared, too many workers can use up resources quickly.