Note: This feature is available in Web Workers
The idea of notification tags is that more than one notification can share the same tag, linking them together. One notification can then be programmatically replaced with another to avoid the users' screen being filled up with a huge number of similar notifications.
var tag = Notification.tag;
Our Using the Notifications API article has a good example of tag usage.
|Notifications API Standard (Notifications API)|
BCD tables only load in the browser