Worker.onmessage
Worker
接口的onmessage
属性表示一个event handler
事件处理函数,当message
事件发生时,该函数被调用。这些事件所属MessageEvent
类型,且当Worker子线程返回一条消息时被调用(比如:从DedicatedWorkerGlobalScope.postMessage
(en-US)函数发出的信息)
注意: 消息被装载到 message
事件对象的data
属性。(译者:即传递的消息参数将被赋值给onmessage
处理函数的事件参数e
中的data
属性)
语法
myWorker.onmessage = function(e) { ... }
范例
下面的代码片段示范用Worker()
构造函数创建一个Worker
对象。当表单的first
输入框的值变更时,消息被传递给worker。myWorker.onmessage
函数用来处理从worker回传的消息。
var myWorker = new Worker('worker.js');
first.onchange = function() {
myWorker.postMessage([first.value,second.value]);
console.log('Message posted to worker');
}
myWorker.onmessage = function(e) {
result.textContent = e.data;
console.log('Message received from worker');
}
在worker.js
中, onmessage
函数用来接收从主线程传递过来的信息:
onmessage = function(e) {
console.log('Message received from main script');
var workerResult = 'Result: ' + (e.data[0] * e.data[1]);
console.log('Posting message back to main script');
postMessage(workerResult);
}
请注意,主线程中必须以myWorker.onmessage
方式调用, 反之 worker.js
脚本中, 只需定义 onmessage
, 因为worker.js全域有效(DedicatedWorkerGlobalScope
).
完整范例,请参考Basic dedicated worker example (run dedicated worker).
规范
规范 | 状态 | 注释 |
---|---|---|
HTML Living Standard Worker.onmessage |
Living Standard | No change from Unknown. |
Unknown Worker.onmessage |
Unknown | Initial definition. |
浏览器兼容性
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.
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参阅
Worker
接口所属。