- From: Boris Zbarsky <bzbarsky@MIT.EDU>
- Date: Tue, 03 Apr 2012 21:09:45 -0400
- To: Jatinder Mann <jmann@microsoft.com>
- CC: James Graham <jgraham@opera.com>, Ian Hickson <ian@hixie.ch>, "arvind@google.com" <arvind@google.com>, "public-web-perf@w3.org" <public-web-perf@w3.org>
On 4/3/12 7:03 PM, Jatinder Mann wrote: >> No, some of them are basic user-facing correctness behavior and have nothing to do with CPU usage... Those are the ones where getting it right on unload matters very much, because the worst case is completely incorrect behavior, not just more CPU hogging. > > Help me understand this one better. What scenarios are you thinking? The main unload scenario for visibilitychange I can think of is saving data before the unload and this is the typical unload event use case. The use cases we've run into are apps that load content of some sort in a tab they control and expose some APIs to that content. Then they want to be able to shut off access to those APIs when the tab is not being viewed by the user. So for example, they might expose an audio API that lets the content in the tab hand off some audio to the app, or an API to allow the content to trigger the device to vibrate; in both cases the API access needs to cut off, and any existing sound or vibration stopped, whenever the content in the tab stops being viewed by the user, whether this happens on tab switch or navigation. Does that help? -Boris
Received on Wednesday, 4 April 2012 01:10:17 UTC