[whatwg] Resource loading in browsing context-less Documents

[Adam Barth]

You can also create contextless documents via XMLHttpRequest.
Presumable <img> elements in XMLHttpRequest-created documents
shouldn't be kicking off network requests!  :)

Adam


On Thu, Oct 4, 2012 at 2:53 PM, Adam Klein <adamk at chromium.org> wrote:
> With DOMImplementation.createDocument and createHTMLDocument, it's
> possible to create Document objects that have no associated browsing
> context. The behavior of elements created by that document is, in some
> cases, well-specified. For example, <script> tags do not execute if
> there is no browsing context
> (http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#concept-n-noscript).
>
> But some behavior is left unspecified, and is implemented differently
> across browsers. For example, the following snippet:
>
>     var doc = document.implementation.createHTMLDocument('myTitle');
>     var img = doc.createElement('img');
>     img.src = 'http://foo.com/myImage.png';
>
> causes the img's src to be fetched by Opera, IE (only tested in 9,
> since previous versions do not implement createHTMLDocument()), while
> neither Gecko nor WebKit load the image. I haven't tested all elements
> that load external resources, but I suspect that the behavior is
> similar for, e.g., <audio> and <video>, where supported (<script src>
> is something of an oddball: only IE tries to load that file when in a
> context-less document).
>
> I'd propose that the Gecko and WebKit behavior is the most sensible.
> For one, it seems more consistent to make everything in the
> context-less Document inactive in the same way <script> is. And at
> least some developers already depend on this behavior (see, e.g., this
> StackOverflow discussion:
> http://stackoverflow.com/questions/7738046/what-for-to-use-document-implementation-createhtmldocument).
>
> Seems like this should be specced in HTML (not sure whether it would
> go in each resource fetching algorithm or somewhere more general).
>
> - Adam