On 5/30/13 12:41 PM, Brady Eidson wrote:
pageshow is a history traversal event, and not a visibility event. I
don’t see a guarantee in any spec that “pageshow” comes after the
document is actually visible.
It comes after it's visible in terms of document.visibilityState, for
pages not in background tabs.
This is true *only* because you and the other people who worked on
integrating page-vis into HTML decided it was true.
No, this is true because the other option is nonsense.
If I'm loading an HTML page in a foreground tab, and it has this script:
<script>alert(document.visibilityState)</script>
Then the alert had better show "visible" in a sane world, and will
definitely happen before pageshow fires.
What I meant was that the pageshow event does *not* inherently mean that
the page is actually visible
Sure thing. Neither does a visibility state change.
Whereas the visibilitychanged event would (presumably?) only
fire once the pixels are painted on the screen.
Of course not. The visibility API does not take occlusion of any sort
into account. It's trivial to have things that claim to be "visible"
for purposes of visibility API that have no pixels anywhere on screen.
Only people without page caches or with a gecko-style page cache could
ship this.
What makes a page cache "gecko-style"? I'm still trying to understand
exactly what prevents you from shipping the currently specified ordering...
-Boris
