Worker()
The Worker()
constructor creates a Worker
object that executes the script at the specified URL. This script must obey the same-origin policy.
Note: that there is a disagreement among browser manufacturers about whether a data URI is of the same origin or not. Though 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
new Worker(aURL, options);
Parameters
- aURL
-
A
USVString
representing the URL of the script the worker will execute. It must obey the same-origin policy. - options Optional
-
An object containing option properties that can be set when creating the object instance. Available properties are as follows:
type
: ADOMString
specifying the type of worker to create. The value can beclassic
ormodule
. If not specified, the default used isclassic
.credentials
: ADOMString
specifying the type of credentials to use for the worker. The value can beomit
,same-origin
, orinclude
. If not specified, or if type isclassic
, the default used isomit
(no credentials required).name
: ADOMString
specifying an identifying name for theDedicatedWorkerGlobalScope
representing the scope of the worker, which is mainly useful for debugging purposes.
Exceptions
- A
SecurityError
is raised if the document is not allowed to start workers, e.g. 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 betext/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 Worker
object using the Worker()
constructor and subsequent usage of the object:
var myWorker = new Worker('worker.js');
first.onchange = function() {
myWorker.postMessage([first.value,second.value]);
console.log('Message posted to worker');
}
For a full example, see our Basic dedicated worker example (run dedicated worker).
Specifications
Specification |
---|
HTML Standard # dom-worker-dev |
Browser compatibility
BCD tables only load in the browser
See also
The Worker
interface it belongs to.