Character coding has some ways,just as "ASCII","GB2312","GBK","UTF-8","UTF-16","ISO-8859-1",and so on.Next I simply introduce these coding way I mentioned.
      "ASCII" is a good English Character coding way that created by ANSI(The American National Standards Institute ),but it is not available for most other charcter aggregation.So many years different  country uses different technology to process the communication of  different character collections.therefore,"GBK","GB2312" .etc.come out."GBK" and "GB2312"  appear just for Chinese."GBK" is a simplified chinese coding method,and "GBK" has little more wide use-range than "GB2312" ,it can be used in complicated chinese,Japanese,Korea.As internationalization is coming,we have to consider a kind of universal character coding way.Next,"Unicode" comes into the world."Unicode"
Unicode has started to replace ASCII, ISO 8859 and EUC at all levels.It enables users to handle not only practically any script and language used on this planet, it also supports a comprehensive set of mathematical and technical symbols to simplify scientific information exchange.