VBScript DateDiff Function

VBScript Function Reference Manual

Definition and Usage

The DateDiff function can return the number of time intervals between two dates.

The DateDiff function is used to calculate the difference between two date and time values, with the calculation method being date2 - date1.

If comparing years, ignore the values below the month; if comparing months, ignore the values below the day, and so on.

Note:The firstdayofweek parameter affects the calculation using the interval symbols 'w' and 'ww'.

Syntax

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

Required. The unit of time interval between date1 and date2 to be calculated.

The following values can be used:

  • yyyy - Year
  • q - Quarter
  • m - Month
  • y - Day of the year
  • d - Day
  • w - Day of the week
  • ww - Week
  • h - Hour
  • n - Minute
  • s - Second
date1,date2 Required. Date expression. Two dates to be used in the calculation.
firstdayofweek

Optional. Defines the number of days in a week, that is, the day of the week.

The following values can be used:

  • 0 = vbUseSystemDayOfWeek - Using the NLS (National Language Support) API settings.
  • 1 = vbSunday - Sunday (default)
  • 2 = vbMonday - Monday
  • 3 = vbTuesday - Tuesday
  • 4 = vbWednesday - Wednesday
  • 5 = vbThursday - Thursday
  • 6 = vbFriday - Friday
  • 7 = vbSaturday - Saturday
firstweekofyear

Optional. Defines the first week of the year.

The following values can be used:

  • 0 = vbUseSystem - Using the NLS (National Language Support) API settings.
  • 1 = vbFirstJan1 - Starting from the week containing January 1st (default).
  • 2 = vbFirstFourDays - Starting from the first week of the year that has at least four days in the New Year.
  • 3 = vbFirstFullWeek - Starting from the first full week of the new year.

Instance

Example 1

document.write(Date & "<br />")
document.write(DateDiff("m",Date,"12/31/2002") & "<br />")
document.write(DateDiff("d",Date,"12/31/2002") & "<br />")
document.write(DateDiff("n",Date,"12/31/2002"))

Output:

1/14/2002
11
351
505440

Example 2

Please note that in the following code, date1>date2:

document.write(Date & "<br />")
document.write(DateDiff("d","12/31/2002",Date))

Output:

1/14/2002
-351

Example 3

How many weeks (start on Monday),
are left between the current date and 10/10/2002
document.write(Date & "<br />")
document.write(DateDiff("w",Date,"10/10/2002",vbMonday))

Output:

1/14/2002
38

VBScript Function Reference Manual