Lets take the example word
präsentation
In Firefox, if I specify that as a CGI parameter, on the receiving end, I recieve:
pr\\303\\244sentation
which decoded as UTF-8 gives me: pr{U+00E4}sentation or my submitted word präsentation.
What does IE give me, well let's see.
pr\\344sentation
which well, doesn't decode as UTF8 because 0o344 is 0xE4.
ä in Unicode is at the codeopint 0xE4. Which as we've seen above, encoded to UTF8 is
0xC3 0xA4
So question boils down to this.
Why does IE9 use ISO-8859-1 instead of UTF8 for non-ASCII characters in URIs?