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 }); } };