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;  
     }  
   
 }