On 6/24/13 2:31 AM, Hajime Morrita wrote:
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 there are at least four possible things to block:
1) Following script execution
2) All following parsing
3) Start of layout if the thing doing the blocking is inside <head>
(modulo explicit layout flushes by the page)
4) Start of painting
<script> does #2, which implies #1 and #3.
<link> does at least #1 per spec and also #3 in Gecko; I'm not sure
whether the spec describes the interaction with #2.
I don't know whether any UAs have anything block #4.
Which of the above do we want imports to block?
-Boris