javascript base64,utf8....

출처:http://ilikefox.tistory.com/1

/**
   *
   *  Base64 encode / decode
   *  http://www.webtoolkit.info/
   *
   **/

   var Base64 = {

    // private property
    _keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",

    // public method for encoding
    encode : function (input) {
     var output = "";
     var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
     var i = 0;

     input = Base64._utf8_encode(input);

     while (i < input.length) {

      chr1 = input.charCodeAt(i++);
      chr2 = input.charCodeAt(i++);
      chr3 = input.charCodeAt(i++);

      enc1 = chr1 >> 2;
      enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
      enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
      enc4 = chr3 & 63;

      if (isNaN(chr2)) {
       enc3 = enc4 = 64;
      } else if (isNaN(chr3)) {
       enc4 = 64;
      }

      output = output +
      this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
      this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);

     }

     return output;
    },

    // public method for decoding
    decode : function (input) {
     var output = "";
     var chr1, chr2, chr3;
     var enc1, enc2, enc3, enc4;
     var i = 0;

     input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

     while (i < input.length) {

      enc1 = this._keyStr.indexOf(input.charAt(i++));
      enc2 = this._keyStr.indexOf(input.charAt(i++));
      enc3 = this._keyStr.indexOf(input.charAt(i++));
      enc4 = this._keyStr.indexOf(input.charAt(i++));

      chr1 = (enc1 << 2) | (enc2 >> 4);
      chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
      chr3 = ((enc3 & 3) << 6) | enc4;

      output = output + String.fromCharCode(chr1);

      if (enc3 != 64) {
       output = output + String.fromCharCode(chr2);
      }
      if (enc4 != 64) {
       output = output + String.fromCharCode(chr3);
      }

     }

     output = Base64._utf8_decode(output);

     return output;

    },

    // private method for UTF-8 encoding
    _utf8_encode : function (string) {
     string = string.replace(/\r\n/g,"\n");
     var utftext = "";

     for (var n = 0; n < string.length; n++) {

      var c = string.charCodeAt(n);

      if (c < 128) {
       utftext += String.fromCharCode(c);
      }
      else if((c > 127) && (c < 2048)) {
       utftext += String.fromCharCode((c >> 6) | 192);
       utftext += String.fromCharCode((c & 63) | 128);
      }
      else {
       utftext += String.fromCharCode((c >> 12) | 224);
       utftext += String.fromCharCode(((c >> 6) & 63) | 128);
       utftext += String.fromCharCode((c & 63) | 128);
      }

     }

     return utftext;
    },

    // private method for UTF-8 decoding
    _utf8_decode : function (utftext) {
     var string = "";
     var i = 0;
     var c = c1 = c2 = 0;

     while ( i < utftext.length ) {

      c = utftext.charCodeAt(i);

      if (c < 128) {
       string += String.fromCharCode(c);
       i++;
      }
      else if((c > 191) && (c < 224)) {
       c2 = utftext.charCodeAt(i+1);
       string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
       i += 2;
      }
      else {
       c2 = utftext.charCodeAt(i+1);
       c3 = utftext.charCodeAt(i+2);
       string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
       i += 3;
      }

     }

     return string;
    },
    
    URLEncode : function (string) {  
           return escape(this._utf8_encode(string));  
       },  
    
       // public method for url decoding  
       URLDecode : function (string) {  
           return this._utf8_decode(unescape(string));  
       }
   }