Created attachment 150318 [details]
Download the STIX fonts (especially the STIXGeneral font)
and open the testcase. You'll see that only the non-plane 1 characters are displayed.
I tested it on Safari 5.1.7 on Windows 7.
Because of this bug, STIX fonts are disabled in MathJax.
Does this work for you in Safari on OS X?
(In reply to comment #1)
> Does this work for you in Safari on OS X?
MathJax only disables these fonts on PC, so I would say it works on OS X. I asked the question on the MathJax issue.
I think non-BMP characters don’t work in any font in Safari on Windows.
See bug 24230.
*** This bug has been marked as a duplicate of bug 24230 ***