W3C home > Mailing lists > Public > public-web-perf@w3.org > May 2013

RE: navigationStart in NavigationTiming

From: Arvind Jain <arvind@google.com>
Date: Wed, 1 May 2013 09:54:22 -0700
Message-ID: <CAOYaDdNdMFPQjaE3qtObwok0dRBM-8GLF5Z3h3BJVBB2DA-FwA@mail.gmail.com>
To: Jatinder Mann <jmann@microsoft.com>
Cc: public-web-perf <public-web-perf@w3.org>
Why are redirect timings zeroed out for this same origin redirect?
 On May 1, 2013 9:27 AM, "Jatinder Mann" <jmann@microsoft.com> wrote:

>  Can you submit a test case? In this example, redirectStart and
> redirectEnd have been zero’d out. An example where they aren’t zero’d out
> might be more helpful. ****
>
> ** **
>
> Thanks,****
>
> Jatinder****
>
> ** **
>
> *From:* Arvind Jain [mailto:arvind@google.com]
> *Sent:* Tuesday, April 30, 2013 7:08 PM
> *To:* public-web-perf
> *Subject:* navigationStart in NavigationTiming****
>
> ** **
>
> I've a question about the definition of navigationStart in the
> specification (
> http://www.w3.org/TR/navigation-timing/#dom-performancetiming-navigationstart
> )****
>
> ** **
>
> It says:****
>
> This attribute must return the time immediately after the user agent
> finishes prompting to unload<http://www.w3.org/TR/html5/browsers.html#prompt-to-unload-a-document> the
> previous document. If there is no previous document, this attribute must
> return the same value as fetchStart<http://www.w3.org/TR/navigation-timing/#dom-performancetiming-fetchstart>
> .****
>
> ** **
>
> The second part of this statement seems odd to me. In case the document in
> question has redirects (e.g. same origin redirects), the value of
> navigationStart will be very different if there was a previous document
> that had to be unloaded vs. not.****
>
> ** **
>
> The difference doesn't make sense.****
>
> ** **
>
> This line was added on Oct 14. 2010. There is one discussion a day before
> that****
>
> http://lists.w3.org/Archives/Public/public-web-perf/2010Oct/0024.html****
>
> which seems to have better text for this but the spec has something else.*
> ***
>
> ** **
>
> I think this inconsistency happened as we revised the definition of
> navigationStart, and we forgot to update the second part of the definition.
> ****
>
> ** **
>
> I checked Chrome and it does the right thing - I load
> http://en.wikipedia.org/ in a new tab and it has a same origin redirect.
> navigationStart is not equal to fetchStart in this case, and in fact occurs
> before redirectStart which in my opinion is correct behavior.****
>
> ** **
>
> How do we fix this?****
>
> ** **
>
> Arvind****
>
Received on Wednesday, 1 May 2013 16:54:50 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:04:35 UTC