var builder = new Blob(data);
builder.append(data);
var blob = builder.getBlob(mimetype || "application/octet-stream");
Replace above code with...
var blob = new Blob(['Hello...'], { type: 'text/css' });
builder.append(data);
var blob = builder.getBlob(mimetype || "application/octet-stream");
Replace above code with...
var blob = new Blob(['Hello...'], { type: 'text/css' });