var count = 0; function do_magic(data) { caches.open("test") .then(function(cache) { return cache.put("http://mochi.test:888/foo", new Response(data.type + "-" + count++)); }) .then(function() { if (count == 1) { postMessage("ready"); } if (data.loop) { setTimeout(function() {do_magic(data); }, 500); } }); } onmessage = function(e) { if (e.data.type == 'page1') { if (e.data.count > 0) { var a = new Worker("worker_suspended.js"); a.postMessage({ type: "page1", count: e.data - 1 }); a.onmessage = function() { postMessage("ready"); } } else { do_magic({ type: e.data.type, loop: true }); } } else if (e.data.type == 'page2') { do_magic({ type: e.data.type, loop: false }); } }