{{APIRef("Web Workers API")}}
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 {{domxref("Window")}} objects — in this case event handlers, the console or the associated {{domxref("WorkerNavigator")}} object. Each WorkerGlobalScope
has its own event loop.
This interface is usually specialized by each worker type: {{domxref("DedicatedWorkerGlobalScope")}} for dedicated workers, {{domxref("SharedWorkerGlobalScope")}} for shared workers, and {{domxref("ServiceWorkerGlobalScope")}} for ServiceWorker. The self
property returns the specialized scope for each context.
Properties
This interface inherits properties from the {{domxref("EventTarget")}} interface and implements properties from {{domxref("WindowTimers")}}, {{domxref("WindowBase64")}}, and {{domxref("WindowEventHandlers")}}.
Standard properties
- {{domxref("WorkerGlobalScope.caches")}} {{readOnlyinline}}
- Returns the {{domxref("CacheStorage")}} object associated with the current context. This object enables service worker functionality such as storing assets for offline use, and generating custom responses to requests.
- {{domxref("WorkerGlobalScope.navigator")}} {{readOnlyinline}}
- Returns the {{domxref("WorkerNavigator")}} associated with the worker. It is a specific navigator object, mostly a subset of the {{domxref("Navigator")}} for browsing scopes, but adapted to workers.
- {{domxref("WorkerGlobalScope.self")}} {{readOnlyinline}}
- Returns a reference to the
WorkerGlobalScope
itself. Most of the time it is a specific scope like {{domxref("DedicatedWorkerGlobalScope")}}, {{domxref("SharedWorkerGlobalScope")}} or {{domxref("ServiceWorkerGlobalScope")}}. - {{domxref("WorkerGlobalScope.location")}} {{readOnlyinline}}
- Returns the {{domxref("WorkerLocation")}} associated with the worker. It is a specific location object, mostly a subset of the {{domxref("Location")}} for browsing scopes, but adapted to workers.
Non-standard properties
- {{domxref("WorkerGlobalScope.performance")}} {{readOnlyinline}} {{Non-standard_inline}}
- Returns the {{domxref("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.
- {{domxref("WorkerGlobalScope.console")}} {{readOnlyinline}} {{Non-standard_inline}}
- Returns the {{domxref("Console")}} associated with the worker.
Event Handlers
This interface inherits event handlers from the {{domxref("EventTarget")}} interface and implements event handlers from {{domxref("WindowTimers")}}, and {{domxref("WindowBase64")}}.
- {{domxref("WorkerGlobalScope.onerror")}}
- Is an {{domxref("EventHandler")}} representing the code to be called when the {{event("error")}} event is raised.
- {{domxref("WorkerGlobalScope.onoffline")}}
- Is an {{domxref("EventHandler")}} representing the code to be called when the {{event("offline")}} event is raised.
- {{domxref("WorkerGlobalScope.ononline")}}
- Is an {{domxref("EventHandler")}} representing the code to be called when the {{event("online")}} event is raised.
- {{domxref("WorkerGlobalScope.onlanguagechange")}}
- An {{domxref("EventHandler")}} fired at the global/worker scope object when the user's preferred languages change.
- {{domxref("WorkerGlobalScope.onclose")}} {{Non-standard_inline}}
- Is an {{domxref("EventHandler")}} representing the code to be called when the {{event("close")}} event is raised.
Methods
This interface inherits methods from the {{domxref("EventTarget")}} interface and implements methods from {{domxref("WindowTimers")}}, {{domxref("WindowBase64")}}, {{domxref("WindowEventHandlers")}}, and {{domxref("GlobalFetch")}}.
Standard methods
- {{domxref("WorkerGlobalScope.close()")}}
- Discards any tasks queued in the
WorkerGlobalScope
's event loop, effectively closing this particular scope. - {{domxref("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
- {{domxref("WorkerGlobalScope.dump()")}} {{non-standard_inline}}
- Allows you to write a message to stdout — i.e. in your terminal. This is the same as Firefox's {{domxref("window.dump")}}, but for workers.
Methods implemented from elsewhere
- {{domxref("WindowBase64.atob()")}}
- Decodes a string of data which has been encoded using base-64 encoding.
- {{domxref("WindowBase64.btoa()")}}
- Creates a base-64 encoded ASCII string from a string of binary data.
- {{domxref("WindowTimers.clearInterval()")}}
- Cancels the repeated execution set using {{domxref("WindowTimers.setInterval()")}}.
- {{domxref("WindowTimers.clearTimeout()")}}
- Cancels the repeated execution set using {{domxref("WindowTimers.setTimeout()")}}.
- {{domxref("GlobalFetch.fetch()")}}
- Starts the process of fetching a resource.
- {{domxref("WindowTimers.setInterval()")}}
- Schedules the execution of a function each X milliseconds.
- {{domxref("WindowTimers.setTimeout()")}}
- Sets a delay for executing a function.
Example
You won't access WorkerGlobalScope
directly in your code; however, its properties and methods are inherited by more specific global scopes such as {{domxref("DedicatedWorkerGlobalScope")}} and {{domxref("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);
Note: Since the global scope of the worker script is effectively the global scope of the worker you are running ({{domxref("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 |
---|---|---|
{{SpecName('HTML WHATWG', '#workerglobalscope', 'WorkerGlobalScope')}} | {{Spec2('HTML WHATWG')}} | No change from {{SpecName("Web Workers")}}. |
{{SpecName('Web Workers', '#workerglobalscope', 'WorkerGlobalScope')}} | {{Spec2('Web Workers')}} | Initial definition. |
{{SpecName('Service Workers')}} | {{Spec2('Service Workers')}} | Defines caches . |
Browser compatibility
{{ CompatibilityTable() }}
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | {{CompatChrome(4)}} | {{CompatGeckoDesktop("1.9.1")}} | 10 | 10.6 | 4 |
ononline , onoffline |
{{CompatVersionUnknown}} | {{CompatGeckoDesktop("29")}} | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
console {{Non-standard_inline}} |
{{CompatVersionUnknown}} | {{CompatGeckoDesktop("29")}} as WorkerConsole {{CompatGeckoDesktop("30")}} as the regular Console |
{{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
performance |
{{CompatVersionUnknown}} | {{CompatGeckoDesktop("34")}} | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
caches |
{{CompatChrome(40)}} | {{CompatUnknown}} | {{CompatNo}} | {{CompatUnknown}} | {{CompatNo}} |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | Firefox OS (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | {{CompatUnknown}} | {{CompatVersionUnknown}} | {{CompatGeckoMobile("1.9.1")}} | 1.0.1 | 10 | 11.5 | 5.1 |
ononline , onoffline |
{{CompatUnknown}} | {{CompatVersionUnknown}} | {{CompatGeckoMobile("29")}} as a specific WorkerConsole {{CompatGeckoMobile("30")}} as the regular Console |
1.4 | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
console {{Non-standard_inline}} |
{{CompatUnknown}} | {{CompatVersionUnknown}} | {{CompatGeckoMobile("29")}} | 1.4 | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
performance |
{{CompatUnknown}} | {{CompatVersionUnknown}} | {{CompatGeckoMobile("34")}} | 2.1 | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
caches |
{{CompatVersionUnknown}} | {{CompatVersionUnknown}} | {{CompatVersionUnknown}} | {{CompatVersionUnknown}} | {{CompatVersionUnknown}} | {{CompatVersionUnknown}} | {{CompatVersionUnknown}} |
See also
- Other global object interface: {{domxref("Window")}}, {{domxref("DedicatedWorkerGlobalScope")}}, {{domxref("SharedWorkerGlobalScope")}}, , {{domxref("ServiceWorkerGlobalScope")}}
- Other Worker-related interfaces: {{domxref("Worker")}}, {{domxref("WorkerLocation")}}, {{domxref("WorkerGlobalScope")}}, and {{domxref("ServiceWorkerGlobalScope")}}.
- Using web workers.