Dammit, and sorry. Try this instead. And yes, that other
function (that preloads the years) is totally unnecessary
so its not included here.
<html>
<head>
<script type="text/javascript">
function populate(objForm,selectIndex) {
timeA = new Date(objForm.year.options[objForm.year.selectedIndex].value, objForm.month.options[objForm.month.selectedIndex].value,1);
timeDifference = timeA - 86400000;
timeB = new Date(timeDifference);
var daysInMonth = timeB.getDate();
for (var i = 0; i < objForm.day.length; i++) {
objForm.day.options[0] = null;
}
for (var i = 0; i < daysInMonth; i++) {
objForm.day.options[i] = new Option(i+1);
}
var fri = new Array();
var count = 0;
for (var i=0; i<daysInMonth; i++) {
tempDate = new Date(objForm.year.options[objForm.year.selectedIndex].value, objForm.month.options[objForm.month.selectedIndex].value-1,i);
if (tempDate.getDay() == 4) {
fri[count] = i+1;
count++;
}
}
for (var i = 0; i < objForm.friday.length; i++) {
objForm.friday.options[0] = null;
}
for (var i = 0; i < fri.length; i++) {
objForm.friday.options[i] = new Option(fri[i]);
}
document.f1.day.options[0].selected = true;
document.f1.friday.options[0].selected = true;
}
</script>
</head>
<body>
<center>
<form name="f1">
<table border="0">
<tr>
<td align=center>
<select name=year onChange="populate(this.form,this.form.month.selectedIndex);">
<option value=1997>1997</option>
<option value=1998>1998</option>
<option value=1999>1999</option>
<option value=2000>2000</option>
<option value=2001>2001</option>
<option value=2002>2002</option>
<option value=2003>2003</option>
<option value=2004 selected>2004</option>
<option value=2005>2005</option>
<option value=2006>2006</option>
</select>
<select name=month onChange="populate(this.form,this.selectedIndex);">
<option value=01>January</option>
<option value=02>February</option>
<option value=03>March</option>
<option value=04>April</option>
<option value=05>May</option>
<option value=06>June</option>
<option value=07>July</option>
<option value=08>August</option>
<option value=09>September</option>
<option value=10>October</option>
<option value=11>November</option>
<option value=12>December</option>
</select>
<select name=day>
<option> </option>
<option> </option>
<option> </option>
<option> </option>
<option> </option>
<option> </option>
<option> </option>
</select>
<select name=friday>
<option> </option>
</select>
</td>
</tr>
</table>
</form>
</center>
</body>
</html>
Oh, you wanted an explanation..
1. I removed the "populateYear()" function and simply
placed 4-digit years in the <select> options.
2. The populate function:
- Obtains a date and substracts by 1 day (0 based days);
The result of the actual date is stored in "timeB".
- The "daysInMonth" var stores the qty of days in the
date and iterates thru this value to populate the "Days"
<select> tag, after it clears it of previous values.
- What I add was an iteration of the "daysInMonth" and,
if that particular day is a Friday, its placed in a new Array,
called "fri".
- I remove one day from the initial selection when the date is
calculated instead of issueing an additional substracting
routine, as the original authors did.
- Once this new array is populated, the values are placed
in the new <select> tag, "friday".
3. The "populate()" function is called anytime a new
year or month is selected.
This sample could be used to pick the specific year, month,
and day and obtain a JS date for subsequent processing.