Created attachment 918 [details]
The spec says: "If a reflecting IDL attribute is a DOMString attribute whose content attribute is defined to contain a URL, then on getting, the IDL attribute must resolve the value of the content attribute relative to the element and return the resulting absolute URL if that was successful, or the empty string otherwise"
None of the major browsers return the empty string.
"If a reflecting IDL attribute is a DOMString attribute whose content attribute is defined to contain a URL, then on getting, the IDL attribute must resolve the value of the content attribute relative to the element and return the resulting absolute URL"
In other words, store whatever value is supplied, and then try to canonicalize the URL relative to that.
This is about what to do with invalid input. E.g. <a href="http://a b/">. That would fail to resolve. So unless the URL resolving algorithm always resolves, we need to handle the case where it fails, somehow.
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Change Description: no spec change
Rationale: What Anne said. So long as the resolving algorithm can fail, then we need to define what happens when it fails.
Adam is currently working on rewriting that algorithm. If he defines it in a way that it never fails, then I can strip this part of the spec. In the meantime... I'll mark this REMIND so I can check this once Adam's work is done.
http://url.spec.whatwg.org/ now defines this. HTML just needs to be updated to refer to it.