web worker

主线程：

var worker = new Worker('work.js');    //新建一个 Worker 线程

//监听worker线程消息
worker.onmessage = function (event) {
  console.log('Received message ' + event.data);
}
//给worker线程发消息
worker.postMessage('Work done!');

worker线程:

//监听主线程的消息
addEventListener('message', function (e) {
  postMessage('You said: ' + e.data);  //给主线程发消息
}, false);

详细使用教程：http://www.ruanyifeng.com/blog/2018/07/web-worker.html