DateDiff Function in VBScript

The DateDiff function returns the number of intervals between two dates.

Syntax:

DateDiff(interval,date1,date2[,firstdayofweek[,firstweekofyear]])

Parameter	Description
interval	Required. The interval you want to use to calculate the differences between date1 and date2Can take the following values: yyyy - Year q - Quarter m - Month y - Day of year d - Day w - Weekday ww - Week of year h - Hour n - Minute s - Second
date1,date2	Required. Date expressions. Two dates you want to use in the calculation
firstdayofweek	Optional. Specifies the day of the week.Can take the following values: 0 = vbUseSystemDayOfWeek - Use National Language Support (NLS) API setting 1 = vbSunday - Sunday (default) 2 = vbMonday - Monday 3 = vbTuesday - Tuesday 4 = vbWednesday - Wednesday 5 = vbThursday - Thursday 6 = vbFriday - Friday 7 = vbSaturday - Saturday
firstweekofyear	Optional. Specifies the first week of the year.Can take the following values: 0 = vbUseSystem - Use National Language Support (NLS) API setting 1 = vbFirstJan1 - Start with the week in which January 1 occurs (default) 2 = vbFirstFourDays - Start with the week that has at least four days in the new year 3 = vbFirstFullWeek - Start with the first full week of the new year

Example 1

The difference between January 31 2009, and January 31 2010:

<script type="text/vbscript">


fromDate="31-Jan-09 00:00:00"
toDate="31-Jan-10 23:59:00"
document.write(DateDiff("yyyy",fromDate,toDate) & "<br />")
document.write(DateDiff("q",fromDate,toDate) & "<br />")
document.write(DateDiff("m",fromDate,toDate) & "<br />")
document.write(DateDiff("y",fromDate,toDate) & "<br />")
document.write(DateDiff("d",fromDate,toDate) & "<br />")
document.write(DateDiff("w",fromDate,toDate) & "<br />")
document.write(DateDiff("ww",fromDate,toDate) & "<br />")
document.write(DateDiff("h",fromDate,toDate) & "<br />")
document.write(DateDiff("n",fromDate,toDate) & "<br />")
document.write(DateDiff("s",fromDate,toDate) & "<br />")


</script>


The output of the code above will be:


1
4
12
365
365
52
53
8783
527039
31622340

Example 2:

How many weeks (start on Monday),

between December 31 2009 and December 31 2012:

<script type="text/vbscript">

fromDate=CDate("2009/12/31")

toDate=CDate("2012/12/31")

document.write(DateDiff("w",fromDate,toDate,vbMonday))

</script>

The output of the code above will be:

156