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.
The requestprogress event of the Fetch API is fired when the HTTP request part of a fetch request makes progress.
| Bubbles | No |
| Cancelable | No |
| Target objects | FetchObserver |
| Interface | Event |
Examples
downloadBtn.addEventListener('click', function() {
fetch(url, {
signal,
observe(observer) {
observer.onrequestprogress = function(e) {
progress.max = e.total;
progress.value = e.loaded;
}
}
}).then( ... ) // do something with the response
});Inheritance
The requestprogress event implements the Event interface — it has available the properties and methods defined on this interface.
Specifications
Not part of a specification yet.
Browser compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|---|
| Basic support |
No support |
No support | No support[1] | 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[1] | No support | No support | No support | No support |
[1] Hidden behind a preference in 55+ Nightly. In about:config, you need to create two new boolean prefs — dom.fetchObserver.enabled and dom.fetchController.enabled — and set the values of both to true.