how to detect the character encoding in a web page ?

[iMath]

在 2012年12月24日星期一UTC+8上午8时34分47秒，iMath写道：
> how to detect the character encoding  in a web page ?
> 
> such as this page 
> 
> 
> 
> http://python.org/

here is one thread that can help me understanding my code 
http://stackoverflow.com/questions/17001407/how-to-detect-the-character-encoding-of-a-web-page-programmatically/17009285#17009285