[whatwg] Deferring image load
svartman95 at gmail.com
Mon Feb 13 10:52:56 PST 2012
On Mon, 13 Feb 2012 14:59:09 -0000, Boris Zbarsky <bzbarsky at mit.edu> wrote:
>> Well, UAs would fetch the images to be displayed first first, and then
>> prefetch images until they have more than a screenful of undisplayed
>> content loaded.
> What does "screenful of undisplayed content" mean for some slide-deck
> site that just moves images in and out of view via script?
I would /expect/ such sites to use a static set of <img>s dynamically
pointed to prefetched <link rel=prefetch> images. With emphasis on expect.
Opera devs should be more knowledgeable on the compatibility problems this
raises, considered they have partly backed out of deferring image loading
> Not knowing the size makes it _impossible_ to do layout correctly.
> Again, UAs would only be able to skip getting images that have explicit
> height and width attributes.
On the contrary, if you've laid out two screenfuls you can guess that
anything after that will not be in the aforeoutlaid* screenfuls.
> And even then, things could be troublesome if the pseudo-clases for
> detecting loading state are added, since those could affect layout...
As I say, there are numerous compatibility problems. If image dimensions
late in the document affect the layout of a previous part of the document,
as you seem to hint at, then hell is loose if we don't know them. Guessing
would be most unfortunate and surprising to layout designers.
* Well, the word does at least conform to the grammar of my native
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