base64.js

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

var Base64 = (function() {
  // Private methods for UTF-8 encoding and decoding
  var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
      utf8Encode = function (string) {
        string = string.replace(/\r\n/g,"\n");
        var utftext = "", n, l, c;
        
        for (n = 0, l = string.length; n < l; n++) {
          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;
      },
      utf8Decode = function (utftext) {
        var string = "", i = 0, 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;
      };
  
  // Public methods for encoding and decoding Base64
  return {
    encode: function (input) {
      var output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;
      
      input = utf8Encode(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 +
        keyStr.charAt(enc1) + keyStr.charAt(enc2) +
        keyStr.charAt(enc3) + keyStr.charAt(enc4);
      }
      
      return output;
    },
    decode: function (input) {
      var output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;
      
      input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
      
      while (i < input.length) {
        enc1 = keyStr.indexOf(input.charAt(i++));
        enc2 = keyStr.indexOf(input.charAt(i++));
        enc3 = keyStr.indexOf(input.charAt(i++));
        enc4 = 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 = utf8Decode(output);
      
      return output;
    }
  };
})();