[whatwg] Proposal for a tab visibility API

Markus Ernst derernst at gmx.ch
Wed Dec 8 14:29:32 PST 2010

Am 08.12.2010 21:40 schrieb Bjartur Thorlacius:
> On Wed, 08 Dec 2010 19:47:34 -0000, Alex Komoroske
>> In particular, there is currently no good way for a web page to detect
>> that
>> it is a background tab and is thus completely invisible to the user,
> Minor semantic nitpick: please use the term /does not have focus/ rather
> than
> /is a background tab/, as the latter is misleading in window managers
> that don't
> use tabs to represent (all) windows. [Ninja'd]

I am not too much familiar with the terminology here, but I humbly think 
that not having focus does not necessarily mean a window is not visible. 
I often have more than one visible window; maybe one where I am 
currently working, and another one at the side with a football game 
streamed or whatever. I wouldn't like the football stream to be stopped 
when this window looses focus. But when the stream gets totally hidden, 
be it that I open a new tab in the same window, or place some other 
window in front of it, the streaming application might want to save 
bandwidth by pausing the streaming of the visuals, while streaming on 
the audio.

Thus, I'd consider an api for detecting the visibility state of every 
HTML element useful (totally visible, partially visible, hidden - or a 
percentage value).

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