Re: TPAC 2011 Web Performance WG 2011-11-01

On Thu, Apr 19, 2012 at 22:33, Boris Zbarsky <bzbarsky@mit.edu> wrote:
> On 4/20/12 1:26 AM, Sreeram Ramachandran wrote:
>>
>> Right, but this is for an iframe. Sorry, I should've been clearer that
>> I was asking about top level documents.
>
> It should work the same exact way for toplevel documents.  Certainly does in
> Gecko.
>
>> contrast, a top-level document that is navigated away from does have
>> its visibilitystate changed, but I haven't been able to find a way to
>> script it.
>
> Just do the same exact thing as my testcase, but use window.open() to get
> the window, instead of an iframe's contentWindow.  And make sure to wait for
> that window to load.

I've tried, and it doesn't work. See the attached test page
(pagecache-test.html). Here's what happens:
1. In Page A (pagecache-test.html), I open a new window to Page B
(another copy of pagecache-test.html), by clicking on "newwin". I
confirm that I can observe Page B by clicking "checkwin" on Page A.
2. In Page B, I navigate to a different page, by clicking on "same
origin". Call this Page C.
3. In Page A, I click "checkwin", but I no longer see the frozen
document (B). Instead, I see C.
4. Okay, maybe the "window" object is live-updating. How about if I
"store" the document object after step 1 (and before step 2) and then
try to use it after step 2? Nope. "checkdoc" shows me C too.

I've tried the above on both Firefox and Safari. Is there another way
to put a page into the pagecache instead of through regular (or
back/forward) navigations?