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Re: [NavigationTiming] few comments

From: Zhiheng Wang <zhihengw@google.com>
Date: Wed, 23 Mar 2011 09:57:29 -0700
Message-ID: <AANLkTi=EoV5JYyrnYDjZerXgFaw+e3tsV6Mfi3Cv2YU_@mail.gmail.com>
To: Olli@pettay.fi
Cc: Olli Pettay <Olli.Pettay@helsinki.fi>, Jonas Sicking <jonas@sicking.cc>, Tony Gentilcore <tonyg@google.com>, public-web-perf@w3.org, jmann@microsoft.com, Nic Jansma <njansma@microsoft.com>
On Wed, Mar 23, 2011 at 8:43 AM, Olli Pettay <Olli.Pettay@helsinki.fi>wrote:

> On 03/23/2011 10:14 AM, Zhiheng Wang wrote:
>
>>   Ollis does remind me a question though. Even though
>> performance.timing should not change
>> when using bfcache (or in cases like the recently implemented chrome
>> prefetch), the current draft
>> implies that the navigation.type will change to BACK_FORWARD, which
>> could confuse the
>> js as well.
>>
>>    maybe navigation.type should remain the same in case of bfcache as
>> well?
>>
>
>
> Based on the current draft, .type should not change.


   duh, you are right. late night is not a good time to think...


>
> "In those cases, the window.performance.timing and
> window.performance.navigation objects must not be altered during the
> navigation."
>
> I still don't quite understand why one kind of navigation
> (navigation from a page to another page in bfcache) shouldn't
> alter the .performance.* objects.
> But if others think that is the behavior we want, that is ok to me.
>
> I do note that Navigation Timing tests don't allow this behavior.
> They assume that when history.forward()/.back() are used, the
>
> navigation.type is TYPE_BACK_FORWARD
>
>
>
> -Olli
>
>
>
>
>
>> cheers,
>> Zhiheng
>>
>>
>>
>>     > And writing tests for BACK_FORWARD becomes really hard,
>>     > since you don't know what value browser returns in .navigation.type.
>>     > Some browsers may return NAVIGATION (because they have bfcache),
>> some
>>     > may return BACK_FORWARD.
>>
>>    The fact that the test has to be a bit more intelligent does not seem
>>    like a reason to complicate the feature exposed to web developers.
>>
>>     > Also, that kind of behavior would actually prevent one
>>     > kind of performance timing - BACK_FORWARD + cached DOM.
>>
>>    What timing is there to do?
>>
>>    / Jonas
>>
>>
>>
>
Received on Wednesday, 23 March 2011 16:58:00 UTC

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