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 {  // unpack four hexets into three octets using index points in b64 
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 = this.utf8_decode(dec); 
return dec; 
}

function utf8_decode ( str_data ) {
    // Converts a UTF-8 encoded string to ISO-8859-1  
    // 
    // version: 909.322
    // discuss at: http://phpjs.org/functions/utf8_decode
    // +   original by: Webtoolkit.info (http://www.webtoolkit.info/)
    // +      input by: Aman Gupta
    // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: Norman "zEh" Fuchs
    // +   bugfixed by: hitwork
    // +   bugfixed by: Onno Marsman
    // +      input by: Brett Zamir (http://brett-zamir.me)
    // +   bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // *     example 1: utf8_decode('Kevin van Zonneveld');
    // *     returns 1: 'Kevin van Zonneveld'
    var tmp_arr = [], i = 0, ac = 0, c1 = 0, c2 = 0, c3 = 0;
    
    str_data += '';
    
    while ( i < str_data.length ) {
        c1 = str_data.charCodeAt(i);
        if (c1 < 128) {
            tmp_arr[ac++] = String.fromCharCode(c1);
            i++;
        } else if ((c1 > 191) && (c1 < 224)) {
            c2 = str_data.charCodeAt(i+1);
            tmp_arr[ac++] = String.fromCharCode(((c1 & 31) << 6) | (c2 & 63));
            i += 2;
        } else {
            c2 = str_data.charCodeAt(i+1);
            c3 = str_data.charCodeAt(i+2);
            tmp_arr[ac++] = String.fromCharCode(((c1 & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
            i += 3;
        }
    }

    return tmp_arr.join('');
}