方案1: User -> Squid ->Web Server

修改squid源碼，加入iconv(big5,gb2312,html page)

		
e.g.1 user (gb.example.org) -> Squid (big5->gb2312) -> web server
e.g.2 user (big5.example.org) -> Squid (gb2312->big5) -> web server