Boris Zbarsky:
What's the document associated with xhr? Is it w1.document, w2.document, or window.document? The concept "the Window object for which the XMLHttpRequest interface object was created" doesn't seem to be defined anywhere....
I don't have a <dfn> for it, but http://dev.w3.org/2006/webapi/WebIDL/#dfn-initial-object says that each global environment has a set of interface objects, and in http://dev.w3.org/2006/webapi/WebIDL/#es-platform-objects I use the term "associated with", but again not wrapped in a <dfn>.
