---
title: ServiceWorkerContainer
slug: Web/API/ServiceWorkerContainer
tags:
  - API
  - Draft
  - Interface
  - NeedsTranslation
  - Offline
  - Reference
  - Service Workers
  - ServiceWorkerContainer
  - TopicStub
  - Workers
translation_of: Web/API/ServiceWorkerContainer
---
<p>{{SeeCompatTable}}{{APIRef("Service Workers API")}}</p>

<p>The <code>ServiceWorkerContainer</code> interface of the <a href="/en-US/docs/Web/API/ServiceWorker_API">ServiceWorker API</a> provides an object representing the service worker as an overall unit in the network ecosystem, including facilities to register, unregister and update service workers, and access the state of service workers and their registrations.</p>

<p>Most importantly, it exposes the {{domxref("ServiceWorkerContainer.register", "ServiceWorkerContainer.register(scriptURL, scope[, base])")}} method used to register service workers, and the {{domxref("ServiceWorkerContainer.controller")}} property used to determine whether or not the current page is actively controlled.</p>

<h2 id="Properties">Properties</h2>

<dl>
 <dt>{{domxref("ServiceWorkerContainer.controller")}} {{readonlyinline}}</dt>
 <dd>Returns a {{domxref("ServiceWorker")}} object if its state is <code>activated</code> (the same object returned by {{domxref("ServiceWorkerRegistration.active")}}). This property returns <code style="font-style: normal;">null</code> if the request is a force refresh (<em>Shift</em> + refresh) or if there is no active worker.</dd>
</dl>

<dl>
 <dt>{{domxref("ServiceWorkerContainer.ready")}} {{readonlyinline}}</dt>
 <dd>Defines whether a service worker is ready to control a page or not. It returns a {{jsxref("Promise")}} that will never reject, which resolves to a {{domxref("ServiceWorkerRegistration")}} with an {{domxref("ServiceWorkerRegistration.active")}} worker.</dd>
</dl>

<h3 id="Event_handlers">Event handlers</h3>

<dl>
 <dt>{{domxref("ServiceWorkerContainer.oncontrollerchange")}}</dt>
 <dd>An event handler fired whenever a {{Event("controllerchange")}} event occurs — when the document's associated {{domxref("ServiceWorkerRegistration")}} acquires a new {{domxref("ServiceWorkerRegistration.active")}} worker.</dd>
 <dt>{{domxref("ServiceWorkerContainer.onerror")}}</dt>
 <dd>An event handler fired whenever an {{Event("error")}} event occurs in the associated service workers.</dd>
 <dt>{{domxref("ServiceWorkerContainer.onmessage")}}</dt>
 <dd>An event handler fired whenever a {{Event("message")}} event occurs — when incoming messages are received to the {{domxref("ServiceWorkerContainer")}} object (e.g. via a {{domxref("MessagePort.postMessage()")}} call.)</dd>
</dl>

<h2 id="Methods">Methods</h2>

<dl>
 <dt>{{domxref("ServiceWorkerContainer.register", "ServiceWorkerContainer.register()")}} </dt>
 <dd>Creates or updates a {{domxref("ServiceWorkerRegistration")}} for the given <code>scriptURL</code>.</dd>
 <dt>{{domxref("ServiceWorkerContainer.getRegistration()")}}</dt>
 <dd>Gets a {{domxref("ServiceWorkerRegistration")}} object whose scope URL matches the provided document URL.  If the method can't return a {{domxref("ServiceWorkerRegistration")}}, it returns a <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" style="text-decoration: underline;" title="The Promise object is used for deferred and asynchronous computations. A Promise is in one of the three states:"><code>Promise</code></a>. </dd>
 <dt>{{domxref("ServiceWorkerContainer.getRegistrations()")}}</dt>
 <dd>Returns all {{domxref("ServiceWorkerRegistration")}}s associated with a <code>ServiceWorkerContainer</code> in an array.  If the method can't return {{domxref("ServiceWorkerRegistration")}}s, it returns a <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" style="text-decoration: underline;" title="The Promise object is used for deferred and asynchronous computations. A Promise is in one of the three states:"><code>Promise</code></a>. </dd>
</dl>

<h2 id="Examples">Examples</h2>

<p>This code snippet is from the <a href="https://github.com/GoogleChrome/samples/blob/gh-pages/service-worker/fallback-response/index.html#L126">service worker fallback-response sample</a> (see <a href="http://googlechrome.github.io/samples/service-worker/fallback-response/">fallback-response live</a>). The code checks to see if the browser supports service workers. Then the code registers the service worker and determines if the page is actively controlled by the service worker. If it isn't, it prompts the user to reload the page so the service worker can take control. The code also reports any registration failures.</p>

<pre class="brush: js">if ('serviceWorker' in navigator) {
  navigator.serviceWorker.register('service-worker.js', {scope: './'}).then(function() {
    if (navigator.serviceWorker.controller) {
      document.querySelector('#status').textContent = 'The service worker is currently handling network operations.';
      showRequestButtons();
    } else {
      document.querySelector('#status').textContent = 'Please reload this page to allow the service worker to handle network operations.';
    }
  }).catch(function(error) {
    document.querySelector('#status').textContent = error;
  });
} else {
  var aElement = document.createElement('a');
  aElement.href = 'http://www.chromium.org/blink/serviceworker/service-worker-faq';
  aElement.textContent = 'unavailable';
  document.querySelector('#status').appendChild(aElement);
}</pre>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('Service Workers', '#service-worker-container', 'ServiceWorkerContainer')}}</td>
   <td>{{Spec2('Service Workers')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari (WebKit)</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatChrome(40.0)}}</td>
   <td>{{ CompatGeckoDesktop("44.0") }}</td>
   <td>{{CompatNo}}</td>
   <td>24</td>
   <td>{{CompatNo}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>Firefox OS</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
   <th>Chrome for Android</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{ CompatGeckoMobile("44.0") }}</td>
   <td>{{ CompatVersionUnknown }}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li><a href="https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorker_API/Using_Service_Workers">Using Service Workers</a></li>
 <li><a class="external external-icon" href="https://github.com/mdn/sw-test">Service workers basic code example</a></li>
 <li><a class="external external-icon" href="https://jakearchibald.github.io/isserviceworkerready/">Is ServiceWorker ready?</a></li>
 <li>{{jsxref("Promise")}}</li>
 <li><a href="https://developer.mozilla.org/en-US/docs/Web/Guide/Performance/Using_web_workers">Using web workers</a></li>
</ul>