Help With day Calculation

Getting the number of Working days is a bit tricky because you have to detect the number of days before and after the weekends on the beginning and ending dates. Holidays are even trickier.

Do a search on "working days". There have already been some posts on the topic. In fact, I wrote a working days calculator at one point, I think it's linked in one of the posts.

Thanks to Niall O'Donovan this problem has been solved:

var oNow = new Date();
var oDay = util.printd("dddd", oNow);

// add 25 working days and make new date object
if (oNow == "Saturday")
{
oNow = new Date(oNow.getFullYear(), oNow.getMonth(), (oNow.getDate() + 35 + 2));
}

else if (oNow == "Sunday")
{
oNow = new Date(oNow.getFullYear(), oNow.getMonth(), (oNow.getDate() + 35 + 1));
}

else
{
oNow = new Date(oNow.getFullYear(), oNow.getMonth(), (oNow.getDate() + 35));
}

// dispaly new date information
sMsg = "In 25 working days it will be " + util.printd("mm/dd/yyyy", oNow);
sMsg += "\n" + "The day of the week will be " + util.printd("dddd", oNow);
app.alert(sMsg, 3, 0);

You still have the public holiday issue. Try starting on December 19, 2010. You will find there are at least 3 days lost to holidays.