On Thu, Oct 15, 2009 at 12:46 PM, Boris Zbarsky <bzbar...@mit.edu> wrote:
> On 10/15/09 3:35 PM, Gregg Tavares wrote: > >> I was wondering if there as been a proposal for either an optional >> argument to setInterval that makes it only callback if the window is >> visible OR maybe a window.setRenderInterval. >> > > You might be interested in > http://groups.google.com/group/mozilla.dev.platform/browse_thread/thread/527d0cedb9b0df7f/57625c94cdf493bffor > some more discussion about approaches to this problem. In particular, > that proposal tries to address overeager animations in visible windows as > well. > > Note, by the way, that testing whether a window is "visible" is not cheap; > testing whether an element is "visible" is even less cheap.... > I'd imagine that UAs could use an overly conservative metric of when things are visible to make things cheaper if/when this is a concern. All that really matters is that the UA never say it isn't visible when any part of the window is visible. I agree that some mechanism to know when things aren't visible would be very useful.