utf-8 and gb2312 converter
此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.greasyfork.icu/scripts/450973/1091107/GB2312UTF8.js
How to GBK(GB2312) and UTF-8 encoding conversion between in JavaScript
following js code show to how to convert text between Simplified Chinese GB 2312 text strings into UTF8 using JavaScript.
Posted in http://freecode-freecode.blogspot.com/2008/11/how-to-gbkgb2312-and-utf-8-encoding.html, mod by https://gist.github.com/19317362/a1d8e40bfb6587463d4d