var dObj=new Date();
var today = dObj.getDate();

today=today+14; //this is where we add the number of days

if (today > 31)
{
today=today-31;
}

//alert(today);
var i;

for(i=1; i<=31; i++)
{
if(i==today)
{
document.write("<option value="+i+" selected >"+i);
}
else
{
document.write("<option value="+i+">"+i);
}
}