SharedWorker()

The SharedWorker() constructor creates a SharedWorker object that executes the script at the specified URL. This script must obey the same-origin policy.

Note: there is disagreement among browser manufacturers about whether a data URI is of the same origin or not. Although Gecko 10.0 (Firefox 10.0 / Thunderbird 10.0 / SeaMonkey 2.7) and later accept data URIs, that's not the case in all other browsers.

Syntax

var myWorker = new SharedWorker(aURL, name);
var myWorker = new SharedWorker(aURL, options);

Parameters

aURL
A DOMString representing the URL of the script the worker will execute. It must obey the same-origin policy.
name Optional
A DOMString specifying an identifying name for the SharedWorkerGlobalScope representing the scope of the worker, which is mainly useful for debugging purposes.
options Optional
An object containing option properties that can set when creating the object instance. Available properties are as follows:
  • type: A DOMString specifying the type of worker to create. The value can be classic or module. If not specified, the default used is classic.
  • credentials: A DOMString specifying the type of credentials to use for the worker. The value can be omit, same-origin, or include. If not specified, or if type is classic, the default used is omit (no credentials required).
  • name: A DOMString specifying an identifying name for the SharedWorkerGlobalScope representing the scope of the worker, which is mainly useful for debugging purposes.

Return value

The created worker.

Exceptions

  • A SecurityError is raised if the document is not allowed to start workers, for example if the URL has an invalid syntax or if the same-origin policy is violated.
  • A NetworkError is raised if the MIME type of the worker script is incorrect. It should always be text/javascript.
  • A SyntaxError is raised if aURL cannot be parsed.

Examples

The following code snippet shows creation of a SharedWorker object using the SharedWorker() constructor and subsequent usage of the object:

var myWorker = new SharedWorker('worker.js');

myWorker.port.start();

first.onchange = function() {
  myWorker.port.postMessage([first.value,second.value]);
  console.log('Message posted to worker');
}

second.onchange = function() {
  myWorker.port.postMessage([first.value,second.value]);
  console.log('Message posted to worker');
}

myWorker.port.onmessage = function(e) {
  result1.textContent = e.data;
  console.log('Message received from worker');
}

For a full example, see our Basic shared worker example (run shared worker.)

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'SharedWorker()' in that specification.
Living Standard

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
SharedWorker() constructorChrome Full support 4Edge Full support 79Firefox Full support 29IE No support NoOpera Full support 10.6Safari No support 5 — 6.1WebView Android No support NoChrome Android No support NoFirefox Android Full support 33Opera Android No support 11 — 14Safari iOS No support 5.1 — 7Samsung Internet Android No support 4.0 — 5.0
Strict MIME type checks for shared worker scriptsChrome ? Edge ? Firefox Full support 70IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android No support NoFirefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android No support No
name optionChrome Full support YesEdge Full support ≤79Firefox Full support 55IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android No support NoFirefox Android Full support 55Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support 4.0 — 5.0

Legend

Full support
Full support
No support
No support
Compatibility unknown
Compatibility unknown

See also