概述WorkerGlobalScopeDedicatedWorkerGlobalScopeSharedWorkerGlobalScopeServiceWorkerGlobalScopeWorkerSharedWorkerServiceWorker工作者线程Worker事件有onerroronmessageonmessageerror方法有postMessageterminate通信使用MessageChannelBroadcastChannel共享工作者线程SharedWorker属性有ports服务者工作线程由ServiceWorkerContainer管理服务者工作线程实例为navigator.serviceWorkerServiceWorkerContainerServiceWorkerRegistrationServiceWorker