This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The SyncEvent interface represents a sync action that is dispatched on the ServiceWorkerGlobalScope of a ServiceWorker. 

This interface inherits from the ExtendableEvent interface.


Creates a new SyncEvent object.


Inherits properties from its ancestor, Event.

SyncEvent.tag Read only
Returns the developer-defined identifier for this SyncEvent.
SyncEvent.lastChance Read only
Returns true if the user agent will not make further synchronization attempts after the current attempt.


Inherits methods from its parent, ExtendableEvent


Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support49 ? ? ? ? ?
SyncEvent() constructor49 ? ? ? ? ?
tag49 ? ? ? ? ?
lastChance49 ? ? ? ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support No49 ? ? ? ?5.0
SyncEvent() constructor No49 ? ? ? ?5.0
tag No49 ? ? ? ?5.0
lastChance No49 ? ? ? ?5.0

Document Tags and Contributors

Contributors to this page: fscholz, tocretpa, rolfedh, jpmedley
Last updated by: fscholz,