考虑这个示例index.html文件。testpagenavigator.serviceWorker.register('sw.js');testpage使用此ServiceWorker，旨在从缓存加载，然后在必要时回退到网络。cacheFirst=(request)=>{varmycache;returncaches.open('mycache').then(cache=>{mycache=cache;cache.match(request);}).then(match=>match||fetch(request,{credentials:'include'})).then(resp