<script type="text/javascript">
   var GB2312UnicodeConverter = { 
    ToUnicode: function (str) {
      return escape(str).toLocaleLowerCase().replace(/%u/gi, '\\u');
      } 
    , ToGB2312: function (str) {
        return unescape(str.replace(/\\u/gi, '%u'));
      } 
  };
    var str = '上海', unicode;
  document.write(str + '<br/>');
  unicode = GB2312UnicodeConverter.ToUnicode(str);
  document.write('汉字转换为Unicode代码：' + unicode + '<br/><br/>');
  document.write('Unicode代码转换为汉字：' + GB2312UnicodeConverter.ToGB2312(unicode));  
</script>