Workers are background tasks that can be easily created and can send messages back to their creators. Creating a worker is as simple as calling the
Worker() constructor, specifying a script to be run in the worker thread.
Of note is the fact that workers may in turn spawn new workers as long as those workers are hosted within the same origin as the parent page. In addition, workers may use
XMLHttpRequest for network I/O, with the exception that the
channel attributes on
XMLHttpRequest always return
For a list of global functions available to workers, see Functions available to workers.
See Using web workers for examples and details.
| || ||An event listener that is called whenever a |
| || ||An event listener that is called whenever an |
The error message
The error message contains three properties:
- A human-readable error message.
- The name of the script file in which the error occurred.
- The line number of the script file on which the error occurred.
The constructor creates a web worker 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) and later accept data URIs, that's not the case in all other browsers.
Worker( in DOMString aStringURL );
- The URL of the script the worker is to execute. It must obey the same-origin policy (or be a data URI for Gecko 10.0 or later).
void postMessage( in JSObject aMessage );
- The object to deliver to the worker; this will be in the data field in the event delivered to the
Immediately terminates the worker. This does not offer the worker an opportunity to finish its operations; it is simply stopped at once.