This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The SyncEvent.tag read-only property of the SyncEvent interface returns the developer-defined identifier for this SyncEvent. This is the value passed in the tag parameter of the SyncEvent() constructor.


var tag = SyncEvent.tag


The developer-defined identifier for this SyncEvent.


Specification Status Comment
Web Background Synchronization
The definition of 'tag' in that specification.
Living Standard Initial definition.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Chrome Full support 49Edge ? Firefox ? IE ? Opera ? Safari ? WebView Android No support NoChrome Android Full support 49Edge Mobile ? Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android Full support 5.0


Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.

Document Tags and Contributors

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