1. Terminology
This specification depends on the Infra Standard. [INFRA]
Some terms used in this specification are defined in the DOM, Fetch, High Resolution Time, HTML, IDL, Service Workers, URL, and Vibration API Standards. [DOM] [FETCH] [HR-TIME] [HTML] [WEBIDL] [SERVICE-WORKERS] [URL] [VIBRATION]
2. Notifications
A notification is an abstract representation of something that happened, such as the delivery of a message.
A notification has an associated service worker registration (null or a service worker registration). It is initially null.
A notification has an associated title (a string).
A notification has an associated direction ("auto
", "ltr
",
or "rtl
").
A notification has an associated language (a string).
A notification has an associated body (a string).
A notification has an associated tag (a string).
A notification has an associated data (a Record).
A notification has an associated timestamp (an EpochTimeStamp
).
Timestamps can be used to indicate the time at which a notification is actual. For example, this could be in the past when a notification is used for a message that couldn’t immediately be delivered because the device was offline, or in the future for a meeting that is about to start.
A notification has an associated origin (an origin).
A notification has an associated renotify preference (a boolean). It is initially false. When true, indicates that the end user should be alerted after the show steps have run with a new notification that has the same tag as an existing notification.
A notification has an associated silent preference (null or a boolean). It is initially null. When true, indicates that no sounds or vibrations should be made. When null, indicates that producing sounds or vibrations should be left to platform conventions.
A notification has an associated require interaction preference (a boolean). It is initially false. When true, indicates that on devices with a sufficiently large screen, the notification should remain readily available until the end user activates or dismisses the notification.
A notification can have these associated graphics: an image URL, icon URL, and badge URL; and their corresponding image resource, icon resource, and badge resource.
An image resource is a picture shown as part of the content of the notification, and should be displayed with higher visual priority than the icon resource and badge resource, though it may be displayed in fewer circumstances.
An icon resource is an image that reinforces the notification (such as an icon, or a photo of the sender).
A badge resource is an icon representing the web application, or the category of the notification if the web application sends a wide variety of notifications. It may be used to represent the notification when there is not enough space to display the notification itself. It may also be displayed inside the notification, but then it should have less visual priority than the image resource and icon resource.
A notification has an associated vibration pattern (a list). It is initially « ».
Developers are encouraged to not convey information through an image, icon, badge, or vibration pattern that is not otherwise accessible to the end user, especially since notification platforms that do not support these features might ignore them.
A notification has associated actions (a list of zero or more actions). An action represents a choice for an end user. Each action has an associated:
- name
- A string.
- title
- A string.
- icon URL
- Null or a URL. It is initially null.
- icon resource
- Null or a resource. It is initially null.
Users may activate actions, as alternatives to activating the notification itself. The maximum number of actions supported is an implementation-defined integer of zero or more, within the constraints of the notification platform.
Since display of actions is platform-dependent, developers are encouraged to make sure that any action an end user can invoke from a notification is also available within the web application.
Some platforms might modify an icon resource to better match the platform’s visual style before displaying it to the end user, for example by rounding the corners or painting it in a specific color. Developers are encouraged to use an icon that handles such cases gracefully and does not lose important information through, e.g., loss of color or clipped corners.
A non-persistent notification is a notification whose service worker registration is null.
A persistent notification is a notification whose service worker registration is non-null.
To create a notification with a settings object, given a string title, NotificationOptions
dictionary options, and environment settings object settings:
-
Let origin be settings’s origin.
-
Let baseURL be settings’s API base URL.
-
Let fallbackTimestamp be the number of milliseconds from the Unix epoch to settings’s current wall time, rounded to the nearest integer.
-
Return the result of creating a notification given title, options, origin, baseURL, and fallbackTimestamp.
To create a notification, given a string title, NotificationOptions
dictionary options, an origin origin, a URL baseURL, and an EpochTimeStamp
fallbackTimestamp:
-
Let notification be a new notification.
-
If options["
silent
"] is true and options["vibrate
"] exists, then throw aTypeError
. -
If options["
renotify
"] is true and options["tag
"] is the empty string, then throw aTypeError
. -
Set notification’s data to StructuredSerializeForStorage(options["
data
"]). -
Set notification’s title to title.
-
Set notification’s origin to origin.
-
If options["
image
"] exists, then parse it using baseURL, and if that does not return failure, set notification’s image URL to the return value. (Otherwise notification’s image URL is not set.) -
If options["
icon
"] exists, then parse it using baseURL, and if that does not return failure, set notification’s icon URL to the return value. (Otherwise notification’s icon URL is not set.) -
If options["
badge
"] exists, then parse it using baseURL, and if that does not return failure, set notification’s badge URL to the return value. (Otherwise notification’s badge URL is not set.) -
If options["
vibrate
"] exists, then validate and normalize it and set notification’s vibration pattern to the return value. -
If options["
timestamp
"] exists, then set notification’s timestamp to the value. Otherwise, set notification’s timestamp to fallbackTimestamp. -
Set notification’s renotify preference to options["
renotify
"]. -
Set notification’s silent preference to options["
silent
"]. -
Set notification’s require interaction preference to options["
requireInteraction
"]. -
Set notification’s actions to « ».
-
For each entry in options["
actions
"], up to the maximum number of actions supported (skip any excess entries): -
Return notification.
2.1. Lifetime and UI integration
The user agent must keep a list of notifications, which is a list of zero or more notifications.
User agents should run the close steps for a non-persistent notification a couple of seconds after they have been created.
User agents should not display non-persistent notification in a platform’s "notification center" (if available).
User agents should persist persistent notifications until they are removed from the list of notifications.
A persistent notification could have the close()
method invoked of one of its Notification
objects.
User agents should display persistent notifications in a platform’s "notification center" (if available).
2.2. Permissions integration
The Notifications API is a powerful feature which is identified by the name "notifications
". [Permissions]
To get the notifications permission state, run these steps:
-
Let permissionState be the result of getting the current permission state with "
notifications
". -
If permissionState is "
prompt
", then return "default
". -
Return permissionState.
2.3. Direction
This section is written in terms equivalent to those used in the Rendering section of HTML. [HTML]
User agents are expected to honor the Unicode semantics of the text of a notification’s title, body, and the title of each of its actions. Each is expected
to be treated as an independent set of one or more bidirectional algorithm
paragraphs when displayed, as defined by the bidirectional algorithm’s rules P1,
P2, and P3, including, for instance, supporting the paragraph-breaking behavior
of U+000A LINE FEED (LF) characters. For each paragraph of the title, body and the title of each of the actions, the notification’s direction provides the higher-level override of
rules P2 and P3 if it has a value other than "auto
". [BIDI]
The notification’s direction also determines the relative order in which the notification’s actions should be displayed to the end user, if the notification platform displays them side by side.
2.4. Language
The notification’s language specifies the primary language for the notification’s title, body and the title of each of its actions. Its value is a string. The empty string indicates that the primary language is unknown. Any other string must be interpreted as a language tag. Validity or well-formedness are not enforced. [BCP47]
Developers are encouraged to only use valid language tags.
2.5. Resources
The fetch steps for a given notification notification are:
-
If the notification platform supports images, fetch notification’s image URL, if image URL is set.
The intent is to fetch this resource similar to an
<img>
, but this needs abstracting.Then, in parallel:
-
Wait for the response.
-
If the response’s internal response’s type is "
default
", then attempt to decode the resource as image. -
If the image format is supported, set notification’s image resource to the decoded resource. (Otherwise notification has no image resource.)
-
-
If the notification platform supports icons, fetch notification’s icon URL, if icon URL is set.
The intent is to fetch this resource similar to an
<img>
, but this needs abstracting.Then, in parallel:
-
Wait for the response.
-
If the response’s internal response’s type is "
default
", then attempt to decode the resource as image. -
If the image format is supported, set notification’s icon resource to the decoded resource. (Otherwise notification has no icon resource.)
-
-
If the notification platform supports badges, fetch notification’s badge URL, if badge URL is set.
The intent is to fetch this resource similar to an
<img>
, but this needs abstracting.Then, in parallel:
-
Wait for the response.
-
If the response’s internal response’s type is "
default
", then attempt to decode the resource as image. -
If the image format is supported, set notification’s badge resource to the decoded resource. (Otherwise notification has no badge resource.)
-
-
If the notification platform supports actions and action icons, then for each action in notification’s actions: if icon URL is non-null, fetch action’s icon URL.
The intent is to fetch this resource similar to an
<img>
, but this needs abstracting.Then, in parallel:
-
Wait for the response.
-
If the response’s internal response’s type is "
default
", then attempt to decode the resource as image. -
If the image format is supported, then set action’s icon resource to the decoded resource. (Otherwise action’s icon resource remains null.)
-
2.6. Showing a notification
The show steps for a given notification notification are:
-
Wait for any fetches to complete and notification’s image resource, icon resource, and badge resource to be set (if any), as well as the icon resources for the notification’s actions (if any).
-
Let shown be false.
-
Let oldNotification be the notification in the list of notifications whose tag is not the empty string and is notification’s tag, and whose origin is same origin with notification’s origin, if any, and null otherwise.
-
If oldNotification is non-null, then:
-
Handle close events with oldNotification.
-
If the notification platform supports replacement, then:
-
Replace oldNotification with notification, in the list of notifications.
-
Set shown to true.
Notification platforms are strongly encouraged to support native replacement as it leads to a better user experience.
-
-
Otherwise, remove oldNotification from the list of notifications.
-
-
If shown is false, then:
-
Append notification to the list of notifications.
-
Display notification on the device (e.g., by calling the appropriate notification platform API).
-
-
If shown is false or oldNotification is non-null, and notification’s renotify preference is true, then run the alert steps for notification.
-
If notification is a non-persistent notification, then queue a task to fire an event named
show
on theNotification
object representing notification.
2.7. Activating a notification
When a notification notification, or one of its actions, is activated by the end user, assuming the underlying notification platform supports activation, the user agent must (unless otherwise specified) run these steps:
-
If notification is a persistent notification, then:
-
Let action be the empty string.
-
If one of notification’s actions was activated by the user, then set action to that action’s name.
- Fire a service worker notification event named "
notificationclick
" given notification and action.
-
-
Otherwise, queue a task to run these steps:
-
Let intoFocus be the result of firing an event named
click
on theNotification
object representing notification, with itscancelable
attribute initialized to true.User agents are encouraged to make
focus()
work from within the event listener for the event namedclick
. -
If intoFocus is true, then the user agent should bring the notification’s related browsing context’s viewport into focus.
-
Throughout the web platform "activate" is intentionally misnamed as "click".
2.8. Closing a notification
When a notification is closed, either by the underlying notification platform or by the end user, the close steps for it must be run.
The close steps for a given notification notification are:
-
If the list of notifications does not contain notification, then abort these steps.
-
Handle close events with notification.
-
Remove notification from the list of notifications.
To handle close events given a notification notification:
-
If notification is a persistent notification and notification was closed by the end user, then fire a service worker notification event named "
notificationclose
" given notification. -
If notification is a non-persistent notification, then queue a task to fire an event named
close
on theNotification
object representing notification.
2.9. Alerting the end user
The alert steps for alerting the end user about a given notification notification are:
-
Perform vibration using notification’s vibration pattern, if any.
3. API
[Exposed =(Window ,Worker )]interface :
Notification EventTarget {constructor (DOMString ,
title optional NotificationOptions = {});
options static readonly attribute NotificationPermission permission ; [Exposed =Window ]static Promise <NotificationPermission >requestPermission (optional NotificationPermissionCallback );
deprecatedCallback static readonly attribute unsigned long maxActions ;attribute EventHandler onclick ;attribute EventHandler onshow ;attribute EventHandler onerror ;attribute EventHandler onclose ;readonly attribute DOMString title ;readonly attribute NotificationDirection dir ;readonly attribute DOMString lang ;readonly attribute DOMString body ;readonly attribute DOMString tag ;readonly attribute USVString image ;readonly attribute USVString icon ;readonly attribute USVString badge ; [SameObject ]readonly attribute FrozenArray <unsigned long >vibrate ;readonly attribute EpochTimeStamp timestamp ;readonly attribute boolean renotify ;readonly attribute boolean ?silent ;readonly attribute boolean requireInteraction ; [SameObject ]readonly attribute any data ; [SameObject ]readonly attribute FrozenArray <NotificationAction >actions ;undefined close (); };dictionary {
NotificationOptions NotificationDirection = "auto";
dir DOMString = "";
lang DOMString = "";
body DOMString = "";
tag USVString ;
image USVString ;
icon USVString ;
badge VibratePattern ;
vibrate EpochTimeStamp ;
timestamp boolean =
renotify false ;boolean ?=
silent null ;boolean =
requireInteraction false ;any =
data null ;sequence <NotificationAction >= []; };
actions enum {
NotificationPermission ,
"default" ,
"denied" };
"granted" enum {
NotificationDirection ,
"auto" ,
"ltr" };
"rtl" dictionary {
NotificationAction required DOMString ;
action required DOMString ;
title USVString ; };
icon callback =
NotificationPermissionCallback undefined (NotificationPermission );
permission
A non-persistent notification is represented by one Notification
object and can be created through Notification
's constructor.
A persistent notification is represented by zero or more Notification
objects and can be created through the showNotification()
method.
3.1. Garbage collection
A Notification
object must not be garbage collected while the list of notifications contains its corresponding notification and it has an event listener whose type is click
, show
, close
, or error
.
3.2. Constructors
The new Notification(title, options)
constructor steps are:
-
If this’s relevant global object is a
ServiceWorkerGlobalScope
object, then throw aTypeError
. -
If options["
actions
"] is not empty, then throw aTypeError
.Actions are only supported for persistent notifications.
-
Let notification be the result of creating a notification with a settings object given title, options, and this’s relevant settings object.
-
Associate this with notification.
-
Run these steps in parallel:
-
If the result of getting the notifications permission state is not "
granted
", then queue a task to fire an event namederror
on this, and abort these steps. -
Run the fetch steps for notification.
-
Run the show steps for notification.
-
3.3. Static members
The static permission
getter steps are to
return the result of getting the notifications permission state.
If you edit standards please refrain from copying the above. Synchronous permissions are like synchronous IO, a bad idea.
Developers are encouraged to use the Permissions query()
method
instead. [Permissions]
const permission = await navigator.permissions.query({name: "notifications"}); if (permission.state === "granted") { // We have permission to use the API… }
The static requestPermission(deprecatedCallback)
method steps are:
-
Let global be the current global object.
-
Let promise be a new promise in this’s relevant Realm.
-
Run these steps in parallel:
-
Let permissionState be the result of requesting permission to use "
notifications
". -
Queue a global task on the DOM manipulation task source given global to run these steps:
-
-
Return promise.
Notifications are the one instance thus far where asking the end user upfront makes sense. Specifications for other APIs should not use this pattern and instead employ one of the many more suitable alternatives.
The static maxActions
getter steps are to
return the maximum number of actions supported.
3.4. Object members
The following are the event handlers (and their corresponding event handler event types) that must be supported as attributes by the Notification
object.
event handler | event handler event type |
---|---|
onclick
| click
|
onshow
| show
|
onerror
| error
|
onclose
| close
|
The close()
method steps are to run the close steps for this’s notification.
The title
getter steps are to return this’s notification’s title.
The dir
getter steps are to return this’s notification’s direction.
The lang
getter steps are to return this’s notification’s language.
The body
getter steps are to return this’s notification’s body.
The tag
getter steps are to return this’s notification’s tag.
The image
getter steps are:
-
If there is no this’s notification’s image URL, then return the empty string.
-
Return this’s notification’s image URL, serialized.
The icon
getter steps are:
-
If there is no this’s notification’s icon URL, then return the empty string.
-
Return this’s notification’s icon URL, serialized.
The badge
getter steps are:
-
If there is no this’s notification’s badge URL, then return the empty string.
-
Return this’s notification’s badge URL, serialized.
The vibrate
getter steps are to return this’s notification’s vibration pattern.
The timestamp
getter steps are to return this’s notification’s timestamp.
The renotify
getter steps are to return this’s notification’s renotify preference.
The silent
getter steps are to return this’s notification’s silent preference.
The requireInteraction
getter steps are to
return this’s notification’s require interaction preference.
The data
getter steps are to return StructuredDeserialize(this’s notification’s data, this’s relevant Realm). If this throws an exception,
then return null.
The actions
getter steps are:
-
Let frozenActions be an empty list of type
NotificationAction
. -
For each entry of this’s notification’s actions:
-
Let action be a new
NotificationAction
. -
If entry’s icon URL is non-null, then set action["
icon
"] to entry’s icon URL, serialized. -
Call Object.freeze on action, to prevent accidental mutation by scripts.
-
Append action to frozenActions.
-
-
Return the result of create a frozen array from frozenActions.
3.5. Examples
3.5.1. Using events from a page
Non-persistent Notification
objects dispatch events during their lifecycle, which developers can use to
generate desired behaviors.
The click
event dispatches when the end user activates a notification.
var not = new Notification("Gebrünn Gebrünn by Paul Kalkbrenner", { icon: "newsong.svg", tag: "song" }); not.onclick = function() { displaySong(this); };
3.5.2. Using actions from a service worker
Persistent notifications fire notificationclick
events on the ServiceWorkerGlobalScope
.
Here a service worker shows a notification with a single "Archive" action, allowing end users to perform this common task from the notification without having to open the website (for example, the notification platform might show a button on the notification). The end user can also activate the main body of the notification to open their inbox.
self.registration.showNotification("New mail from Alice", { actions: [{action: 'archive', title: "Archive"}] }); self.addEventListener('notificationclick', function(event) { event.notification.close(); if (event.action === 'archive') { silentlyArchiveEmail(); } else { clients.openWindow("/inbox"); } }, false);
3.5.3. Using the tag
member for multiple instances
Web applications frequently operate concurrently in multiple instances, such as when an end user
opens a mail application in multiple browser tabs. Since the desktop is a shared resource, the
notifications API provides a way for these instances to easily coordinate, by using the tag
member.
Notifications which represent the same conceptual event can be tagged in the same way, and when both are shown, the end user will only receive one notification.
Instance 1 | Instance 2 | // Instance notices there is new mail. | new Notification("New mail from John Doe", | { tag: 'message1' }); | | | // Slightly later, this instance notices | // there is new mail. | new Notification("New mail from John Doe", | { tag: 'message1' });
The result of this situation, if the user agent follows the algorithms here, is a single notification "New mail from John Doe".
3.5.4. Using the tag
member for a single instance
The tag
member can also be used by a single instance of an
application to keep its notifications as current as possible as state changes.
For example, if Alice is using a chat application with Bob, and Bob sends multiple messages while Alice is idle, the application may prefer that Alice not see a desktop notification for each message.
// Bob says "Hi" new Notification("Bob: Hi", { tag: 'chat_Bob' }); // Bob says "Are you free this afternoon?" new Notification("Bob: Hi / Are you free this afternoon?", { tag: 'chat_Bob' });
The result of this situation is a single notification; the second one
replaces the first having the same tag. In a platform that queues notifications
(first-in-first-out), using the tag allows the notification to also maintain its
position in the queue. Platforms where the newest notifications are shown first,
a similar result could be achieved using the close()
method.
4. Service worker API
dictionary {
GetNotificationOptions DOMString = ""; };
tag partial interface ServiceWorkerRegistration {Promise <undefined >showNotification (DOMString ,
title optional NotificationOptions = {});
options Promise <sequence <Notification >>getNotifications (optional GetNotificationOptions = {}); }; [
filter Exposed =ServiceWorker ]interface :
NotificationEvent ExtendableEvent {(
constructor DOMString ,
type NotificationEventInit );
eventInitDict readonly attribute Notification notification ;readonly attribute DOMString action ; };dictionary :
NotificationEventInit ExtendableEventInit {required Notification ;
notification DOMString = ""; };
action partial interface ServiceWorkerGlobalScope {attribute EventHandler onnotificationclick ;attribute EventHandler onnotificationclose ; };
The showNotification(title, options)
method steps are:
-
Let global be this’s relevant global object.
-
Let promise be a new promise in this’s relevant Realm.
-
If this’s active worker is null, then reject promise with a
TypeError
and return promise. -
Let notification be the result of creating a notification with a settings object given title, options, and this’s relevant settings object. If this threw an exception, then reject promise with that exception and return promise.
-
Set notification’s service worker registration to this.
-
Run these steps in parallel:
-
If the result of getting the notifications permission state is not "
granted
", then queue a global task on the DOM manipulation task source given global to reject promise with aTypeError
, and abort these steps. -
Run the fetch steps for notification.
-
Run the show steps for notification.
-
Queue a global task on the DOM manipulation task source given global to resolve promise with undefined.
-
-
Return promise.
The getNotifications(filter)
method steps are:
-
Let global be this’s relevant global object.
-
Let realm be this’s relevant Realm.
-
Let origin be this’s relevant settings object’s origin.
-
Let promise be a new promise in realm.
-
Run these steps in parallel:
-
Let tag be filter["
tag
"]. -
Let notifications be a list of all notifications in the list of notifications whose origin is same origin with origin, whose service worker registration is this, and whose tag, if tag is not the empty string, is tag.
-
Queue a global task on the DOM manipulation task source given global to run these steps:
-
Let objects be a list.
-
For each notification in notifications, in creation order, create a new
Notification
object with realm representing notification, and append it to objects. -
Resolve promise with objects.
-
-
-
Return promise.
This method returns zero or more new Notification
objects which might represent
the same underlying notification of Notification
objects already in existence.
To fire a service worker notification event named name given a notification notification, and an optional string action (default
the empty string): run Fire Functional Event given name, NotificationEvent
, notification’s service worker registration, and the following
initialization:
notification
- A new
Notification
object representing notification. action
- action
The notification
getter steps are to
return the value it was initialized to.
The action
getter steps are to return the
value it was initialized to.
The following is the event handler (and its corresponding event handler event type) that must be supported as attribute by the ServiceWorkerGlobalScope
object:
event handler | event handler event type |
---|---|
onnotificationclick
| notificationclick
|
onnotificationclose
| notificationclose
|
Acknowledgments
Thanks to Addison Phillips, Aharon (Vladimir) Lanin, Alex Russell, Anssi Kostiainen, Arkadiusz Michalski, Boris Zbarsky, David Håsäther, Doug Turner, Drew Wilson, Ehsan Akhgari, Frederick Hirsch, Ian Hickson, Jake Archibald, James Graham, John Mellor, Jon Lee, Jonas Sicking, Michael Cooper, Michael Henretty, Michael™ Smith, Michael van Ouwerkerk, Mike Taylor, Nicolás Satragno, Olli Pettay, Peter Beverloo, Philip Jägenstedt, Reuben Morais, Rich Tibbett, Robert Bindar, 박상현 (Sanghyun Park), Simon Pieters, Theresa O’Connor, timeless, and triple-underscore for being awesome.
This standard is written by Anne van Kesteren (Apple, annevk@annevk.nl). An earlier iteration was written by John Gregg (Google, johnnyg@google.com).
Intellectual property rights
Copyright © WHATWG (Apple, Google, Mozilla, Microsoft). This work is licensed under a Creative Commons Attribution 4.0 International License. To the extent portions of it are incorporated into source code, such portions in the source code are licensed under the BSD 3-Clause License instead.
This is the Living Standard. Those interested in the patent-review version should view the Living Standard Review Draft.