This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
You would never run this function yourself, rather it would be run internally as a result of an observe parameter being defined on a fetch request
Again, you would never run this method by yourself. Refer to the
FetchObserver page for a valid observer usage example
Not part of a specification yet.
|Feature||Chrome||Edge||Firefox (Gecko)||Internet Explorer||Opera||Safari (WebKit)|
|No support||No support||No support||
|Feature||Android||Android Webview||Edge||Firefox Mobile (Gecko)||IE Phone||Opera Mobile||Safari Mobile||Chrome for Android|
|Basic support||No support||No support||No support||No support||No support||No support||No support||No support|
 Hidden behind a preference in 55+ Nightly. In about:config, you need to create two new boolean prefs —
dom.fetchController.enabled — and set the values of both to