ServiceWorkerGlobalScope.onactivate - Web APIs 编辑

The onactivate property of the ServiceWorkerGlobalScope interface is an event handler fired whenever an activate event occurs (when the service worker activates). This happens after installation, when the page to be controlled by the service worker refreshes.

Syntax

ServiceWorkerGlobalScope.onactivate = function(event) { ... };

Examples

The following snippet shows how you could use an activate event handler to upgrade a cache.

then.addEventListener('activate', function(event) {
  var cacheWhitelist = ['v2'];

  event.waitUntil(
    caches.forEach(function(cache, cacheName) {
      if (cacheWhitelist.indexOf(cacheName) == -1) {
        return caches.delete(cacheName);
      }
    })
  );
});

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using Service Workers
• Service workers basic code example
• Is ServiceWorker ready?
• Promise
• Using web workers