this.EXPORTED_SYMBOLS = ['checkFromJSM']; this.checkFromJSM = function checkFromJSM(ok, is, finish) { let worker = new ChromeWorker("jsm_url_worker.js"); worker.onmessage = function(event) { if (event.data.type == 'finish') { finish(); } else if (event.data.type == 'status') { ok(event.data.status, event.data.msg); } } var self = this; worker.onerror = function(event) { is(event.target, worker); ok(false, "Worker had an error: " + event.data); self.worker.terminate(); finish(); }; worker.postMessage(0); }