Worker

Worker interface of the Web 工作者 API represents a background task that can be created via script, which can send messages back to its creator. Creating a worker is done by calling the Worker("path/to/worker/script") 构造函数。

Workers may themselves spawn new workers, as long as those workers are hosted at the same origin as the parent page. (Note: nested workers are not yet implemented in WebKit ).

Not all interfaces and functions are available to scripts inside a Worker . Workers may use XMLHttpRequest for network communication, but its responseXML and channel attributes are always null . ( fetch is also available, with no such restrictions.)

构造函数

Worker()
Creates a dedicated web worker that executes the script at the specified URL. This also works for Blob URLs .

特性

Inherits properties from its parent, EventTarget , and implements properties from AbstractWorker .

事件处理程序

AbstractWorker.onerror
An EventListener called whenever an ErrorEvent of type error bubbles through to the worker. This is inherited from AbstractWorker .
Worker.onmessage
An EventListener called whenever a MessageEvent of type message bubbles through the worker — i.e. when a message is sent to the parent document from the worker via DedicatedWorkerGlobalScope.postMessage . The message is stored in the event's data 特性。
Worker.onmessageerror
Is an EventHandler representing the code to be called when the messageerror event is raised.

方法

Inherits methods from its parent, EventTarget , and implements methods from AbstractWorker .

Worker.postMessage()
Sends a message — consisting of any JavaScript object — to the worker's inner scope.
Worker.terminate()
Immediately terminates the worker. This does not let worker finish its operations; it is halted at once. ServiceWorker instances do not support this method.

Events

message
Fires when the worker's parent receives a message from that worker.
Also available via the onmessage 特性。
messageerror
Fires when a Worker object receives a message that can't be deserialized .
Also available via the onmessageerror 特性。
rejectionhandled
Fires every time a Promise rejects, regardless of whether or not there is a handler to catch the rejection.
Also available through the onrejectionhandled event handler property.
unhandledrejection
Fires when a Promise rejects with no handler to catch the rejection.
Also available using the onunhandledrejection event handler property.

范例

The following code snippet creates a Worker object using the Worker() constructor, then uses the worker object:

var myWorker = new Worker('/worker.js');
var first = document.querySelector('input#number1');
var second = document.querySelector('input#number2');
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 ).

规范

规范 状态 Comment
HTML Living Standard
The definition of 'Worker' in that specification.
实时标准

浏览器兼容性

Support varies for different types of workers. See each worker type's page for specifics.

更新 GitHub 上的兼容性数据
Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
Worker Chrome 4 Edge 12 Firefox 3.5 IE 10 Opera 10.6 Safari 4 WebView Android 4 Chrome Android 18 Firefox Android 4 Opera Android 11 Safari iOS 5.1 Samsung Internet Android 1.0
Worker() 构造函数 Chrome 4 Edge 12 Firefox 3.5 IE 10 Opera 10.6 Safari 4 WebView Android 4 Chrome Android 18 Firefox Android 4 Opera Android 11 Safari iOS 5.1 Samsung Internet Android 1.0
message event Chrome 4 Edge 12 Firefox 3.5 IE 10 Opera 10.6 Safari 4 WebView Android 4 Chrome Android 18 Firefox Android 4 Opera Android 11.5 Safari iOS 5.1 Samsung Internet Android 1.0
messageerror event Chrome 60 Edge 18 Firefox 57 IE ? Opera 47 Safari ? WebView Android 60 Chrome Android 60 Firefox Android 57 Opera Android 47 Safari iOS ? Samsung Internet Android 8.0
onmessage Chrome 4 Edge 12 Firefox 3.5 IE 10 Opera 10.6 Safari 4 WebView Android 4 Chrome Android 18 Firefox Android 4 Opera Android 11 Safari iOS 5.1 Samsung Internet Android 1.0
onmessageerror Chrome 60 Edge 18 Firefox 57 IE ? Opera 47 Safari ? WebView Android 60 Chrome Android 60 Firefox Android 57 Opera Android 44 Safari iOS ? Samsung Internet Android 8.0
postMessage Chrome Yes Edge 12 Firefox Yes IE 10
10
Internet Explorer does not support Transferable 对象。
Opera 47 Safari Yes WebView Android Yes Chrome Android Yes Firefox Android Yes Opera Android 44 Safari iOS Yes Samsung Internet Android Yes
terminate Chrome 4 Edge 12 Firefox 3.5 IE 10 Opera 10.6 Safari 4 WebView Android 4 Chrome Android 18 Firefox Android 4 Opera Android 11 Safari iOS 5.1 Samsung Internet Android 1.0

图例

完整支持
完整支持
兼容性未知
兼容性未知
见实现注意事项。

Cross-origin worker error behaviour

In early versions of the spec, loading a cross-origin worker script threw a SecurityError . Nowadays, an error event is thrown instead. Find out how to deal with this in Loading cross-origin worker now fires error event instead of throwing; worker in sandboxed iframe no longer allowed .

另请参阅