function decode64(input) {
    var output = "";
    var hex = "";
    var chr1, chr2, chr3 = "";
    var enc1, enc2, enc3, enc4 = "";
    var i = 0;
	var b64array = "ABCDEFGHIJKLMNOP" +
           "QRSTUVWXYZabcdef" +
           "ghijklmnopqrstuv" +
           "wxyz0123456789+/" +
           "=";

    var base64test = /[^A-Za-z0-9\+\/\=]/g;
    if (base64test.exec(input)) {
        $("#message").html("There were invalid base64 characters in the input text.\n" +
              "Valid base64 characters are A-Z, a-z, 0-9, '+', '/',and '='\n" +
              "Expect errors in decoding.");
    } else {
        $("#message").html("");
    }
    input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

    do {
        enc1 = b64array.indexOf(input.charAt(i++));
        enc2 = b64array.indexOf(input.charAt(i++));
        enc3 = b64array.indexOf(input.charAt(i++));
        enc4 = b64array.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);
        }
    
        chr1 = chr2 = chr3 = "";
        enc1 = enc2 = enc3 = enc4 = "";
    
    } while (i < input.length);

    return unescape(output);
}