Currently testing IE10 in Windows 8 developer preview and uploader is not working on HTML5, HTML4 is OK, FLASH is OK.
IE10 doesn't support XHR Level 2 just yet (at least it didn't, do you know if something has changed?)
Here we can see it should http://caniuse.com/xhr2
Related question in plupload forum http://www.plupload.com/punbb/viewtopic.php?id=1014
That's nice! I'll see were I can push it further.
IE10 should be working, the version shipped in the consumer preview has support for XHR2 and the File/Blob objects.
Ok, I managed to finally get it installed. And Plupload HTML5 just worked. Even resize works out of the box. So...? Maybe you could retry with the latest Windows 8 build?
It doesn't seem to work cross-domain.
It doesn't depend on HTML5 runtime only, your server (to which you are planning to do a cross-domain upload), should be properly prepared as well.
I have CORS set up and Webkit/Gecko browsers can upload fine.
In IE10's console I get "SCRIPTS: Access is denied".
There is nothing in the code that may constrain it, so it should be something else...