'好'.charCodeAt(0).toString(16)
"597d"

var str="Hello world!"
document.write(str.charCodeAt(1))
//结果：101
'好哦'.charCodeAt(0).toString(16)
"597d"
'好哦'.charCodeAt(1).toString(16)
"54e6"

'\u54e6'
"哦"

function toUnicodeFun(data){
 if(data == '' || typeof data == 'undefined') return '请输入汉字';
  var str ='';
  for(var i=0;i<data.length;i++){
   str+="\\u"+data.charCodeAt(i).toString(16);
  }
  return str;
}
var resultUnicode = toUnicodeFun('中国'); // \u4e2d\u56fd
console.log(resultUnicode);

function toChineseWords(data){
  if(data == '' || typeof data == 'undefined') return '请输入十六进制unicode';
  data = data.split("\\u");
  var str ='';
  for(var i=0;i<data.length;i++){
    str+=String.fromCharCode(parseInt(data[i],16).toString(10));
  }
  return str;
}
var resultChineseWords = toChineseWords("\u4e2d\u56fd");
console.log(resultChineseWords);//中国

var GB2312UnicodeConverter={
  ToUnicode:function(str){
    return escape(str).toLocaleLowerCase().replace(/%u/gi,'\\u');
  },
  ToGB2312:function(str){
    return unescape(str.replace(/\\u/gi,'%u'));
  }
};
var result = GB2312UnicodeConverter.ToUnicode('中国'); //\u4e2d\u56fd
var result2 = GB2312UnicodeConverter.ToUnicode(result); //%5cu4e2d%5cu56fd

function toUnicode(s){
  return s.replace(/([\u4E00-\u9FA5]|[\uFE30-\uFFA0])/g,function(newStr){
    return "\\u" + newStr.charCodeAt(0).toString(16);
  });
}