Hi,
The one plugin we know of which causes this is the HTMLValidator plugin
for Firefox (which uses HTMLTidy), when it hits an iframe with a "data:"
src url.
http://users.skynet.be/mgueury/mozilla/download.html- Do you have this installed?
- Can you try disabling it, and then seeing if you get the error?
This simple test page (no YUI code) will also cause the same error if
you have the plugin installed:
http://yuiblog.com/sandbox/yui/v241/examples/container/HTMLValidatorError.html
We can go from there.
Thanks,
Satyen