W3C home > Mailing lists > Public > public-web-perf@w3.org > June 2014

Re: navigationStart and the actual start of the navigation

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Fri, 27 Jun 2014 11:11:51 -0400
Message-ID: <53AD89B7.3090304@mit.edu>
To: public-web-perf@w3.org
On 6/27/14, 9:39 AM, Przemysław Pietrzkiewicz wrote:
> "If there is no previous document, this attribute must return the time
> the current document is created."
> What does "time the current document is created" mean? If read in terms
> of terminology we use in Chromium/Blink, that would be the time when we
> start loading the page in the renderer.

The only case in the spec when there is no previous document is when the 
document in question is the initial about:blank in the navigation 
context.  So "time the current document is created" is when the 
navigation context is created.

> But this can happen long time after the "open link in new tab" button is
> clicked.

Yes, agreed.  Navigation via window.open() has the same issue: it might 
take a while to actually open a window.  It would be nice to try to 
define this somehow in a way that makes sense for all browsers...

> "This attribute must return the time when the user agent determines that
> the navigation will happen. For navigations from existing documents,
> this is the time when the user agent finishes prompting to unload the
> previous document."

All navigations except initial about:blank are "from existing documents" 
in spec terms, so this phrasing wouldn't help the problem you're trying 
to solve, sadly.

Received on Friday, 27 June 2014 15:12:20 UTC

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