if ('caches' in window) {
caches.keys()
.then(function(keyList) {
return Promise.all(keyList.map(function(key) {
return caches.delete(key);
}));
})
}
if(window.navigator && navigator.serviceWorker) {
navigator.serviceWorker.getRegistrations()
.then(function(registrations) {
for(let registration of registrations) {
registration.unregister();
}
});
}