[whatwg] Show upload progress

[Joaquin Cuenca Abela]

Matthew wrote:
> 
> A much easier and more consistent approach would be for the browser to 
> show the upload progress itself. Complain to your friendly local 
> browser vendor.

Oh, and to add another item to the previous list:

* There is only one progress bar in the browser.

The thing is you may have the main upload going targetting a frame, and have some xmlhttprequest / iframe downloads going on the background. It will drive crazy the browser progress bar. Only the page author knows what's the most probable big, blocking upload/download in the page.