This feature is not Baseline because it does not work in some of the most widely-used browsers.
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
Note: This feature is available in Web Workers.
The downloaded read-only property of the BackgroundFetchRegistration interface returns the size in bytes that has been downloaded, initially 0.
If the value of this property changes, the progress event is fired at the associated BackgroundFetchRegistration object.
A number.
Logging this property to the console returns the number of bytes downloaded.
console.log(bgFetch.downloaded);
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | WebView on iOS | |
downloaded |
74 | 79 | No | 62 | No | 74 | No | 53 | No | 11.0 | No | No |
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https://developer.mozilla.org/en-US/docs/Web/API/BackgroundFetchRegistration/downloaded