As other comments have pointed out, this behavior is enabled by `requestIdleCallback`.
MDN has a good example and looks like this is not supported by Safari -
https://developer.mozilla.org/en-US/docs/Web/API/Background_...
MDN has a good example and looks like this is not supported by Safari -
https://developer.mozilla.org/en-US/docs/Web/API/Background_...
https://github.com/hiroki0525/idle-task/blob/main/src/index....
References - https://developer.chrome.com/blog/using-requestidlecallback/...
Gecko is the engine behind Firefox and is maintained by Mozilla, so it has a good number of open source contributors that help fix issues when they are found. It also has some issues occasionally but since it has only a ~3% usage these days you don't get as many complaints.
Blink is used by Chromium (which includes Edge, Chrome, Opera, Brave, and Samsung browsers). It has the biggest market share and probably the most people actively paid to work on it.
Webkit is currently only used by Safari and maintained by Apple alone. (Also all iOS browsers have to use webkit which is why iOS chrome has a lot of the same bugs as iOS safari etc). Apple has a conservative approach to Webkit and doesn't implement as many new features or standards as quickly as the other engines. It has the biggest non blink engine market share so it's usually the outlier when it comes to support issues.
Before 2013 Chromium was webkit based, but that year they made a fork and took their engine in a new direction so Webkit lost some of its previous maintainers.
This is far too generous. They intentionally withold features in an effort to push people towards their app store.
It's currently an experimental feature that can be enabled, so hopefully Apple will enable it by default in 2023.