It's quite easy to implement. See the code snippets below
<script>
base64Keys = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_=";
base64Encode = function(input) {
var chr1, chr2, chr3, enc1, enc2, enc3, enc4, i, output;
output = "";
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 + (base64Keys.charAt(enc1)) + (base64Keys.charAt(enc2)) + (enc3 < 64 ? base64Keys.charAt(enc3) : '') + (enc4 < 64 ? base64Keys.charAt(enc4) : '');
}
return output;
};
utf8Encode = function(string) {
var c, s, utftext, _i, _len, _ref;
string = string.replace(/\r\n/g, "\n");
utftext = "";
_ref = string.split('');
for (_i = 0, _len = _ref.length; _i < _len; _i++) {
s = _ref[_i];
c = s.charCodeAt(0);
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;
};
</script>
