function base64_decode(data) {
var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
var o1,
o2,
o3,
h1,
h2,
h3,
h4,
bits,
i = 0,
ac = 0,
dec = "",
tmp_arr = [];
if (!data) {
return data;
}
data += "";
do {
h1 = b64.indexOf(data.charAt(i++));
h2 = b64.indexOf(data.charAt(i++));
h3 = b64.indexOf(data.charAt(i++));
h4 = b64.indexOf(data.charAt(i++));
bits = (h1 << 18) | (h2 << 12) | (h3 << 6) | h4;
o1 = (bits >> 16) & 0xff;
o2 = (bits >> 8) & 0xff;
o3 = bits & 0xff;
if (h3 == 64) {
tmp_arr[ac++] = String.fromCharCode(o1);
} else if (h4 == 64) {
tmp_arr[ac++] = String.fromCharCode(o1, o2);
} else {
tmp_arr[ac++] = String.fromCharCode(o1, o2, o3);
}
} while (i < data.length);
dec = tmp_arr.join("");
dec = utf8_decode(dec);
return dec;
}