Date Functions
There are some inherent ASP date functions which are very
powerful. They are very similar to the inherent SQL date functions
bearing the same name, although the syntax varies slightly.
To get the current date, you can use the Date keyword. To
get the current date and time, use the Now keyword. Here is
a line of code that would print out the current date:
Response.Write("Today is " & Date)
To get the month, year, or day of any date, you can use the built in
functions Month, Year, or Day. For example, if
today were the 4th of December, 1998 (as today happens to be), here is how
you could print out 12/4/1998:
Response.Write(Month(Date) & "/" & Day(Date) & "/" & Year(Date))
One of the most useful date functions is DateSerial.
DateSerial allows you to create a date from three parameters: the year,
month, and day. While this may not seem that spectacular, it is, and you
will see why in a moment.
Let's look at a quick line of code which would create a date of 3/14/98
and store it in a variable name SomeDate:
Dim SomeDate
SomeDate = DateSerial(1998, 3, 14)
As you can probably see, DateSerial expects first the year, then the
month, then the date. If we were to print out SomeDate, it would appear
as "3/14/98" (or perhaps different, based on your machines regional
settings).
Now, for the real power with DateSerial. Let's say you want to make the
variable SomeDate equal to the last day of the month two months ago from
today. This could be a very tricky operation, because what if the current
month was January, then you would have to go back a year. If the current
month was April, you'd have to worry if it was a leap year or not.
However, with DateSerial, none of these worries arise. Let's look at a
line of code which will set SomeDate equal to the date described above:
SomeDate = DateSerial(Year(Date), Month(Date) - 1, 1 - 1)
You may be furrowing your brow as you read this, but at least let me try
to explain first. The DateSerial is forming a date for the current year
(Year(Date)), for the month one month before the current month (i.e. the
Month(Date) - 1, for the first day before the first day of the month
(which is the last day of the month before the month before the current
month. If that sentence doesn't have you confused, let me try once
again.
The above syntax is giving you...
The first day before the first day of the month before the month before
the current month for the current year.
If I didn't confuse you by now you are truly a wiz.
