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 (for historical reasons other JavaScript MIME types may be accepted).
  • 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
HTML Standard (HTML)
# dom-sharedworker-dev

Browser compatibility

BCD tables only load in the browser

See also