var base64s = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

function base64_encode(decStr)
{
 var bits;
 var dual;
 var i = 0;
 var encOut = '';
 while(decStr.length >= i + 3)
 {
  bits = (decStr.charCodeAt(i++) & 0xff) <<16 |
         (decStr.charCodeAt(i++) & 0xff) <<8  |
          decStr.charCodeAt(i++) & 0xff;
  encOut += base64s.charAt((bits & 0x00fc0000) >>18) +
            base64s.charAt((bits & 0x0003f000) >>12) +
            base64s.charAt((bits & 0x00000fc0) >> 6) +
            base64s.charAt((bits & 0x0000003f));
 }
 if(decStr.length -i > 0 && decStr.length -i < 3)
 {
  dual = Boolean(decStr.length -i -1);
  bits = ((decStr.charCodeAt(i++) & 0xff) <<16) |
         (dual ? (decStr.charCodeAt(i) & 0xff) <<8 : 0);
  encOut += base64s.charAt((bits & 0x00fc0000) >>18) +
            base64s.charAt((bits & 0x0003f000) >>12) +
            (dual ? base64s.charAt((bits & 0x00000fc0) 
            >>6) : '=') +
            '=';
 }
 return(encOut);
}