You can go and try using a web server that works internally in 16-bit Unicode (UTF-16)
and serves web pages in many languages in either UTF-8 (default) or many other
codepages. (Now that ICU was mentioned already...)
Go to http://oss.software.ibm.com/developerworks/opensource/icu/localeexplorer/
and see for yourself.
For comparison of Japanese, try looking at Japanese locale data in UTF-8 and then in
Shift-JIS.
UTF-8:
http://oss.software.ibm.com/developerworks/opensource/icu/localeexplorer/en_US/?_=ja_JP&
Shift-JIS:
http://oss.software.ibm.com/developerworks/opensource/icu/localeexplorer/en_US/Shift_JIS/?_=ja_JP
Feel free to use this as a test for your client to see how their browsers deal with
such pages in different codepages.
ICU and the locale explorer are available as open-source
(http://oss.software.ibm.com/icu/).
markus
PS: No other library (like xIUA) was used or harmed in the code for locale explorer...