Windows jscript base64 encoder. Drag and drop files you wanna encode to this .js file.

encoder.js

var fsDoOverwrite     = true  // Overwrite file with base64 code
var fsAsASCII         = false // Create base64 code file as ASCII file
var adTypeBinary      = 1     // Binary file is encoded

function encode(from, to) {
    var inputStream = WScript.CreateObject("ADODB.Stream");
    inputStream.Type = adTypeBinary
    inputStream.Open();
    inputStream.LoadFromFile(from);
    
    var xml = WScript.CreateObject("MSXml2.DOMDocument");
    var element = xml.createElement("Base64Data");
    element.dataType = "bin.base64";
    
    element.nodeTypedValue = inputStream.Read();
    
    inputStream.Close();
    
    var fileSystem = WScript.CreateObject("Scripting.FileSystemObject");
    var outputStream = fileSystem.CreateTextFile(to, fsDoOverwrite, fsAsASCII);
    
    outputStream.Write(element.text.replace(/\n/g, ""));
    outputStream.Close();
}

function getTxtName(name) {
    return name + ".txt";
}

function main() {
    var args = WScript.Arguments;
    for(i = 0; i < args.length; ++i) {
        encode(args(i), getTxtName(args(i)));
    }
}

main();