HTML5 File Upload Progress - Client Side Only

I have noticed that the new XMLHttpRequest object supports an 'onprogress' event in firefox. Is it possible to utilize part of the new HTML5 File api's to get开发者_JS百科 an upload progress bar without any server-side modifications required?

I believe in principle yes, though I haven't tried it out yet.

What's going to be a problem is that XMLHttpRequest#send() takes a Unicode string and encodes it as UTF-8. It doesn't give you the ability to send pure binary, and most binary files like images are not going to happen to be valid UTF-8 sequences.

So probably you'd be using what the FileAPI spec calls a “binary string” (bytes treated as ISO-8859-1, so each charCodeAt corresponds to a byte), recoded to UTF-8. This would end up around 50% bigger than a plain file upload. Is it worth the slower upload to get the progress report?

(God, if only browsers had a better UI to show how the upload was going, none of the endless scripting/Flash/Java/ActiveX nonsense would ever have been necessary. Come on, browser vendors, is a nice big info popup with a progress bar really too much to ask for?)

Yes, in theory, although I would have to question the accuracy since Internet speed generally fluctuates (more-so if you aren't wired). It would probably jump around alot.

Then again, what is an accurate progress bar? I'd like to see one in Windows before I see one online!