I have implemented the standard Flash version of the Uploadify jQuery plugin within a canvas app on Facebook.
The upload is working perfectly fine in Firefox. But when I try to start an upload in Chrome or IE, it fails with this message in the console:
Uncaught Call to StartUpload failed
For those not familiar with Facebook canvas apps, it's PHP pages running within an iframe in Facebook which might be leading to this problem - though it doesn't work when run outside of a frame either.
I'm also getting these errors in the Chrome console:
Unsafe JavaScript attempt to access frame with URL https://apps.facebook.com/[app name]/[page name]/ from frame with URL https://[app domain]/[page path]. The frame being accessed set 'document.domain' to 'facebook.com', but the frame requesting access did not. Both must set 'document.domain' to the same value to allow access.
Any ideas what might be happening? I've already tried setting up a crossdomain.xml for Flash with no success.