The register()
method of the ServiceWorkerContainer
interface creates or updates a ServiceWorkerRegistration
for the given scriptURL
.
If successful, a service worker registration ties the provided script URL to a scope, which is subsequently used for navigation matching. You can call this method unconditionally from the controlled page. I.e., you don't need to first check whether there's an active registration.
There is frequent confusion surrounding the meaning and use of scope. Since a service worker can't have a scope broader than its own location, only use the scope
option when you need a scope that is narrower than the default.
Syntax
serviceWorkerContainer.register(scriptURL, options) .then(function(serviceWorkerRegistration) { ... });
Parameters
scriptURL
- The URL of the service worker script. The registered service worker file needs to have a valid JavaScript MIME type.
options
Optional- An object containing registration options. Currently available options are:
scope
: AUSVString
representing a URL that defines a service worker's registration scope; that is, what range of URLs a service worker can control. This is usually a relative URL. It is relative to the base URL of the application. By default, thescope
value for a service worker registration is set to the directory where the service worker script is located. See the Examples section for more information on how it works.
Return value
A Promise
that resolves with a ServiceWorkerRegistration
object.
Examples
The examples described here should be taken together to get a better understanding of how service workers scope applies to a page.
The following example uses the default value of scope
(by omitting it). The service worker code in this case, if included in example.com/index.html
, will control example.com/index.html
, as well as pages underneath it, like example.com/product/description.html
.
if ('serviceWorker' in navigator) { // Register a service worker hosted at the root of the // site using the default scope. navigator.serviceWorker.register('/sw.js').then(function(registration) { console.log('Service worker registration succeeded:', registration); }, /*catch*/ function(error) { console.log('Service worker registration failed:', error); }); } else { console.log('Service workers are not supported.'); }
The following code, if included in example.com/index.html
, at the root of a site, would apply to exactly the same pages as the example above. Remember the scope, when included, uses the page's location as its base.
Alternatively, if this code were included in a page at example.com/product/description.html
, with the Javascript file residing at example.com/product/sw.js
, then the service worker would only apply to resources under example.com/product
.
if ('serviceWorker' in navigator) { // declaring scope manually navigator.serviceWorker.register('/sw.js', {scope: './'}).then(function(registration) { console.log('Service worker registration succeeded:', registration); }, /*catch*/ function(error) { console.log('Service worker registration failed:', error); }); } else { console.log('Service workers are not supported.'); }
There is frequent confusion surrounding the meaning and use of scope. Since a service worker can't have a scope broader than its own location, only use the scope
option when you need a scope that is narrower than the default.
The following code, if included in example.com/index.html
, at the root of a site, would only apply to resources under example.com/product
.
if ('serviceWorker' in navigator) { // declaring scope manually navigator.serviceWorker.register('/sw.js', {scope: '/product/'}).then(function(registration) { console.log('Service worker registration succeeded:', registration); }, /*catch*/ function(error) { console.log('Service worker registration failed:', error); }); } else { console.log('Service workers are not supported.'); }
However, Servers can remove this restriction by setting a Service-Worker-Allowed header on the service worker script, and then you can specify a max scope for that service worker above the service worker's location.
Specifications
Specification | Status | Comment |
---|---|---|
Service Workers The definition of 'ServiceWorkerContainer: register' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
register | Chrome Full support 40 | Edge
Full support
17
| Firefox
Full support
44
| IE No support No | Opera Full support 27 | Safari Full support 11.1 | WebView Android Full support 40 | Chrome Android Full support 40 | Firefox Android Full support 44 | Opera Android Full support 27 | Safari iOS Full support 11.3 | Samsung Internet Android Full support 4.0 |
Legend
- Full support
- Full support
- No support
- No support
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.