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Re: <img src="..." defer>

From: James Simonsen <simonjam@google.com>
Date: Mon, 22 Apr 2013 17:19:16 -0700
Message-ID: <CAPVJQikY_wRkd4APMV+pJhQoKSzJFc99UqoQ42OsuZj=oyHMmg@mail.gmail.com>
To: Jake Archibald <jakearchibald@google.com>
Cc: Jatinder Mann <jmann@microsoft.com>, public-web-perf <public-web-perf@w3.org>
On Fri, Apr 19, 2013 at 11:13 AM, Jake Archibald

> On 19 Apr 2013 18:29, "Jatinder Mann" <jmann@microsoft.com> wrote:
> > Have we decided on whether a ‘defer’ resource shouldn’t delay the load
> event [1]? I can’t think of a reason why this would be bad, but can
> definitely see the performance benefits of allowing scripts that trigger
> off the onload to run sooner.
> Guy Podjarny made the case against
> https://www.w3.org/Bugs/Public/show_bug.cgi?id=17842
Not that he's here, but to his point, I'd say we should warn developers to
only use defer/delay/lazy when they don't care about them affecting the
spinner and load event. It should primarily be used for resources that are
obviously offscreen to begin with.

I trust RUM tools will adapt to lazy loading and provide useful feedback to
developers about how well lazy images are working in the wild.

> Personally, I don't think they should block load, especially if they can
> delay loading for a long time or indefinitely.

Received on Tuesday, 23 April 2013 00:19:43 UTC

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