Weird IE6 Date Comparison bug

[guilhermelemmi]

I'm creating a function that will take a start date, a period duration (in months)and a maximum date, and will calculate the periods start and end dates until reaching the maximum date.
For instance, I would give 01/01/2008, period equals 3 months and maximum date equals 01/01/2009, and the method should return periods like "01/01/2008-03/31/2008","04/01/2008-06/30/2008","07/01/2008-09/30/2008","10/01/2008-12/31/2008".

The code looks like:

function getPeriods(p_startDate, p_duration, p_maxDate)
{
  var periodsList = [];
  var nextStartDate, endDate, period, year, month, day;
  var startDt = p_startDate; 
  do {
    year = startDt.getUTCFullYear();
    month = startDt.getUTCMonth();
    day = startDt.getUTCDate();
 
    nextStartDate = new Date();
    nextStartDate.setFullYear(year, month + p_duration, day);
 
    endDate = new Date(nextStartDate);
    endDate.setDate(endDate.getDate()-1);
 
    if(endDate >= p_maxDate) {
      endDate = p_maxDate;
    }
    period = {"Start":startDt,"End":endDate};
    periodsList[periodsList.length] = period;
    startDt = nextStartDate;
    //alert(periodsList.length);
  }
  while(p_maxDate > endDate); 
 
  return periodsList;
}
 
function printPeriods(p_periodsList)
{
  alert(">>>" + p_periodsList.length);
  //for(var i=0; i< p_periodsList.length ; i++)
  //{
    //alert("Start: " + p_periodsList[i].Start + "\nEnd: " + p_periodsList[i].End);
  //}
}
 
var st = new Date;
st.setFullYear(2008,0,1);
var max = new Date;
max.setFullYear(2009,0,1);
max.setDate(max.getDate()-1);
printPeriods(getPeriods(st, 3, max));

However, when I run the code, the alert window will display ">>> 5" in IE6, while it displays ">>> 4" in Firefox, which is the expected length.

To make things even stranger, if I uncomment the "alert" in the last line of the "do" block, IE will run the correct number of loops, displaying ">>> 4" in the end.

Any ideas or workarounds?

Thanks in advance!

[acoder]

Weird indeed. This also occurs in IE7. Since it works with the alert, there must be some timing bug. It may work if you use a small timeout.