EN
このコンテンツは設定された言語で表示できません。英語版のページが表示されます。

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

The WorkerGlobalScope object has these events.

EventDescription
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.

MethodDescription
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.

PropertyAccess typeDescription

indexedDB

Read-only

Allows access to the Indexed Database API, as implemented by a Windows Store app using JavaScript.

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.

 

 

表示:
© 2014 Microsoft