Re: HTML imports and rendering

Fwiw, the polyfill here <https://github.com/Polymer/HTMLImports/> does not
adhere to the standard on this issue: the polyfill does not block rendering.

In Polymer itself, we set body opacity to 0 until components are ready to
simulate spec behavior.

My expectation is that the specified behavior is as Morita-san describes.

Scott


On Sun, Jun 23, 2013 at 11:31 PM, Hajime Morrita <morrita@google.com> wrote:

> Hello,
>
> HTML Imports spec relies on the concept of "things that is blocking
> scripts".
> In HTML, <link>-ed styles are blocking scripts. So All styles that precede
> a <script> are loaded before the script execution.
>
> http://www.whatwg.org/specs/web-apps/current-work/multipage/semantics.html#the-link-element
>
> HTML Imports behaves in similar manner. The <link>s to HTML Import block
> following <script> execution.
> So in practice, linked imports are loaded before the page rendering like
> liked styles are applied before that,
> because most of the pages will have some kind of initialization script.
>
>
> Does this make sense?
>
> # @dglazkov correct me if I'm wrong.
>
> --
> morrita
>
>
>
> On Mon, Jun 24, 2013 at 6:45 AM, Guy Bedford <guybedford@googlemail.com>wrote:
>
>> HTML imports don't seem to block the rendering of the HTML page at all.
>>
>> If this is the case, custom elements must always be progressively
>> enhanced with a flash of content and style. This is not always ideal. It
>> can make sense for certain custom elements to only display after having
>> their style and initial scripts run.
>>
>> Has there been any discussion around having attributes on the link tag to
>> specify blocking behaviour at all? Surely it is important to have control
>> over HTML rendering at this level?
>>
>> Yes, build tools / multiplexing should occur for these blocking parts
>> when used in production for performance reasons, but I don't believe the
>> fact that it can become a performance issue is reason enough to force all
>> components to use progressive enhancement. Or am I missing something here?
>>
>
>
>
> --
> morrita
>