The WorkerGlobalScope
interface of the Web Workers API is an interface representing the scope of any worker. Workers have no browsing context; this scope contains the information usually conveyed by Window
objects — in this case event handlers, the console or the associated WorkerNavigator
object. Each WorkerGlobalScope
has its own event loop.
This interface is usually specialized by each worker type: DedicatedWorkerGlobalScope
for dedicated workers, SharedWorkerGlobalScope
for shared workers, and ServiceWorkerGlobalScope
for ServiceWorker. The self
property returns the specialized scope for each context.
Properties
This interface inherits properties from the EventTarget
interface and WindowOrWorkerGlobalScope
and WindowEventHandlers
mixins.
Standard properties
WorkerGlobalScope.navigator
Только для чтения
- Returns the
WorkerNavigator
associated with the worker. It is a specific navigator object, mostly a subset of theNavigator
for browsing scopes, but adapted to workers. WorkerGlobalScope.self
Только для чтения- Returns a reference to the
WorkerGlobalScope
itself. Most of the time it is a specific scope likeDedicatedWorkerGlobalScope
,SharedWorkerGlobalScope
orServiceWorkerGlobalScope
. WorkerGlobalScope.location
Только для чтения- Returns the
WorkerLocation
associated with the worker. It is a specific location object, mostly a subset of theLocation
for browsing scopes, but adapted to workers.
Non-standard properties
WorkerGlobalScope.performance
Только для чтения- Returns the
Performance
associated with the worker. It is a regular performance object, except that only a subset of its property and methods are available to workers. WorkerGlobalScope.console
Только для чтения- Returns the
Console
associated with the worker.
Properties implemented from elsewhere
WindowOrWorkerGlobalScope.caches
Только для чтения- Returns the
CacheStorage
object associated with the current context. This object enables functionality such as storing assets for offline use, and generating custom responses to requests. WindowOrWorkerGlobalScope.indexedDB
Только для чтения- Provides a mechanism for applications to asynchronously access capabilities of indexed databases; returns an
IDBFactory
object. WindowOrWorkerGlobalScope.isSecureContext
Только для чтения- Returns a boolean indicating whether the current context is secure (
true
) or not (false
). WindowOrWorkerGlobalScope.origin
Только для чтения- Returns the global object's origin, serialized as a string. (This does not yet appear to be implemented in any browser.)
Events
error
- Fired when an error occured.
Also available via theWorkerGlobalScope.onerror
property. offline
- Fired when the browser has lost access to the network and the value of
navigator.onLine
switched tofalse
.
Also available via theWorkerGlobalScope.onoffline
property. online
- Fired when the browser has gained access to the network and the value of
navigator.onLine
switched totrue
.
Also available via theWorkerGlobalScope.ononline
property. languagechange
- Fired at the global/worker scope object when the user's preferred languages change.
Also available via theWorkerGlobalScope.onlanguagechange
property.
close
- Is an
EventHandler
representing the code to be called when theclose
event is raised.
Also available via theWorkerGlobalScope.onclose
property. rejectionhandled
- An event handler for handled
Promise
rejection events.
Also available via theWorkerGlobalScope.onrejectionhandled
property. unhandledrejection
- An event handler for unhandled
Promise
rejection events.
Also available via theWorkerGlobalScope.onunhandledrejection
property.
Methods
This interface inherits methods from the EventTarget
interface and WindowOrWorkerGlobalScope
and WindowEventHandlers
mixins.
Standard methods
WorkerGlobalScope.importScripts()
- Imports one or more scripts into the worker's scope. You can specify as many as you'd like, separated by commas. For example:
importScripts('foo.js', 'bar.js');
Non-standard methods
WorkerGlobalScope.dump()
- Allows you to write a message to stdout — i.e. in your terminal. This is the same as Firefox's
window.dump
, but for workers.
Methods implemented from elsewhere
WindowOrWorkerGlobalScope.atob()
- Decodes a string of data which has been encoded using base-64 encoding.
WindowOrWorkerGlobalScope.btoa()
- Creates a base-64 encoded ASCII string from a string of binary data.
WindowOrWorkerGlobalScope.clearInterval()
- Cancels the repeated execution set using
WindowOrWorkerGlobalScope.setInterval()
. WindowOrWorkerGlobalScope.clearTimeout()
- Cancels the delayed execution set using
WindowOrWorkerGlobalScope.setTimeout()
. WindowOrWorkerGlobalScope.createImageBitmap()
- Accepts a variety of different image sources, and returns a
Promise
which resolves to anImageBitmap
. Optionally the source is cropped to the rectangle of pixels originating at (sx, sy) with width sw, and height sh. WindowOrWorkerGlobalScope.fetch()
- Starts the process of fetching a resource from the network.
WindowOrWorkerGlobalScope.setInterval()
- Schedules a function to execute every time a given number of milliseconds elapses.
WindowOrWorkerGlobalScope.setTimeout()
- Schedules a function to execute in a given amount of time.
Deprecated methods
WorkerGlobalScope.close()
- Discards any tasks queued in the
WorkerGlobalScope
's event loop, effectively closing this particular scope. In newer browser versions,close()
is available onDedicatedWorkerGlobalScope
andSharedWorkerGlobalScope
instead. This change was made to stopclose()
being available on service workers, as it isn't supposed to be used there and always throws an exception when called (see баг 1336043).
Example
You won't access WorkerGlobalScope
directly in your code; however, its properties and methods are inherited by more specific global scopes such as DedicatedWorkerGlobalScope
and SharedWorkerGlobalScope
. For example, you could import another script into the worker and print out the contents of the worker scope's navigator
object using the following two lines:
importScripts('foo.js');
console.log(navigator);
Since the global scope of the worker script is effectively the global scope of the worker you are running (DedicatedWorkerGlobalScope
or whatever) and all worker global scopes inherit methods, properties, etc. from WorkerGlobalScope
, you can run lines such as those above without specifying a parent object.
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard Определение 'WorkerGlobalScope' в этой спецификации. |
Живой стандарт |
Browser compatibility
BCD tables only load in the browser
See also
- Other global object interface:
Window
,DedicatedWorkerGlobalScope
,SharedWorkerGlobalScope
, ,ServiceWorkerGlobalScope
- Other Worker-related interfaces:
Worker
,WorkerLocation
,WorkerGlobalScope
, andServiceWorkerGlobalScope
. - Using web workers.