"Jonas Sicking" <[EMAIL PROTECTED]>
The problem lies in if the XHR implementation doesn't know the total size.
Then it can't give you a percentage.
Something needs to be defined to be done in this situation, not knowing the
size is likely the standard in many uses of XHR.
If it gives you the number of bytes transferred do far, the user or the
script can figure out the progress even if the XHR implementation doesn't
know the total size.
Exactly, if we look at existing implementations, the IE onProgress event
(not available in a default security environment) provides currentBytes and
totalBytes (or 0) which I've used for preloading resources.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/com/html/07b3e629-a558-4a0e-8307-ca922f56e00c.asp
Macromedia Flash does the same
http://livedocs.macromedia.com/flash/8/main/wwhelp/wwhimpl/common/html/wwhelp.htm?context=LiveDocs_Parts&file=00002219.html
If there was always a content-length, then there'd be no problem with just
having a percentage, however there's not. It's another problem with trying
to re-use properties from a defunct specification that considered such a
tight range of use cases as the DOM3 L&S - it was about parsing XML
documents, not downloading web content.
Jim.
