This line doesn't work correctly when you use Chile - Santiago - GMT on Windows bar-clock:

var printDate = new Date(drawYear, drawMonth, leadDays);

If you use the following values, print the same date:

var drawYear=2010;

var drawMonth=10;

var leadDays = -22;

Now, if you use the followings values, you get the same result:

var drawYear=2010;

var drawMonth=10;

var leadDays = -23;

Maybe this error is caused by Windows API.