> But, by the same token, XHR upload of FormData[1] already serves this use > case in a more flexible way. You can even make a FormData from the contents > of an html form and then add additional File objects. Making the change would > (afaict) not serve any new use cases. At most it would be a convenience.
Agreed, it's a convenience, the same could be do with a sync XHR followed by a location.reload(). The readonly restriction exists for historical reasons, and dropping it seems like a small change that makes the web platform more usable. Nico
