Summary
Including the date and/or time on a web page can
be a subtle yet valuable addition when designing a web site. The addition of the
date to the home page can create the impression that a site is constantly being
updated with new content since each time a visitor loads the page, the current
date will be displayed.
In this tutorial I'll teach you how to add the
date and time to your ASP pages using the VBScript FormatDateTime() function.
I'll explain how the function works, teach you how to integrate it into your ASP
pages and illustrate the output you'll get depending on the arguments you pass.
I'll round out the tutorial of the FormatDateTime() function by covering a few
limitations that it has, which might or might not be a big deal depending on
your specific needs.
Just FYI, this article assumes you know basic
HTML and how to add ASP scripts to your web pages.
The FormatDateTime() Function
Microsoft provides a ton of predefined VBScript
functions designed to reduce coding time. The FormatDateTime() function is one
of those powerful functions and is really easy to use, too. This function uses
the following format:
FormatDateTime(date, format)
There are two arguments the function accepts:
date and format. Table 1-1 below describes these arguments in greater detail:
Table 1-1:
The FormatDateTime() function and its arguments
| Argument |
Argument
Description |
| date |
This argument is required and
can be any valid date expression such as Date or Now
|
| format |
This format constant or format value
specifies how the date and/or time will be displayed on your ASP page.
When specifying the format argument, you
can either type the Visual Basic constant name (name in left column), or
the constant's corresponding value (0 - 4, from the middle column). They
do the same thing, it's just less typing if you use the value.
|
Constant
|
Format Value
|
Format
Description |
| vbGeneralDate |
0
|
This
is the default. Not specifying a value or specifying 0 will
produce a date in the format of mm/dd/yy.
If the date expression is Now, it will also return the time,
after the date, in hh:mm:ss PM/AM format.
|
| vbLongDate |
1
|
This is my personal favorite :-)
Passing this value will produce a date in the format of
weekday, month day, year*
* The year is Y2K
compliant :-).
|
| vbShortDate |
2
|
Passing this value returns a date
formatted just like the default of 0 (mm/dd/yy).
|
| vbLongTime |
3
|
Passing
this value returns the time in hh:mm:ss PM/AM format.
|
| vbShortTime |
4
|
Passing
this value returns military time in this format hh:mm |
|
Table 1-1 is a good reference once you've got a
feel for how the FormatDateTime() function works or if you're an experienced
programmer. For those of you that aren't clear on how all the information in
table 1-1 relates to "real world" implementations, let's take a look
at some examples:
Returning the Current Date
If you would like to display the current date,
here are a few different ways to do it along with the results they produce:
<%= FormatDateTime(Date) %> returns:
(You would get the same result by coding this: <%= FormatDateTime(Date,
0) %>)
<%= FormatDateTime(Date, 1) %> returns:
<%= FormatDateTime(Date, 2)%> returns:
Returning the Current Time
If you would like to return the current time,
here are a couple of ways to do that:
<%= FormatDateTime(Now, 3)%> returns: 5:41:14 AM
<%= FormatDateTime(Now, 4)%> returns: 05:41
Returning the Current Date and Time
If you would like to return the current date and
time together, here's how to do just that:
<%= FormatDateTime(Now) %> returns: 2/9/2010 5:41:14 AM
If you're like me, you probably don't like the
way the date and time displays above; it's not very cool looking, is it? In
cases like this, you can actually include two FormatDateTime() functions next to
each other, in order to get the date and time in a more desriptive format, like
this:
<%= FormatDateTime(Date, 1) %> <%=
FormatDateTime(Now, 3)%> returns:
5:41:14 AM
Adding the code to your page
Integrating the code into your ASP pages is
really easy; here is how the code would look on a page with basic HTML to
display the date:
<html>
<head>
<title>Here's the date</title>
</head>
<body>
Thank you for coming to this page. The current
date is: <%= FormatDateTime(Date, 1) %>
</body>
</html>
Limitations of the FormatDateTime() function
The FormatDateTime() function is an extremely
handy bit of code that can help you add a touch of flair almost instantly. I
would like to mention four limitations that stick out in my mind, which may be
an issue to you (or your clients) depending on the project at hand:
Limitation 1: The unneeded zero
On the first through ninth days of a month the
day shows up in the format of "Month 01, Year". I know it seems like a
small thing but trust me, it's can be a big deal to some.
Limitation 2: Only basic formatting allowed
You are limited to basic formatting of the string
that's returned by the FormatDateTime() function. Since the date and/or time
function returns is a single string, you can bold, italicize and change the
whole date/time by adding HTML or style sheet tags around it, but you can't
change the display properties for a single part (e.g., the month).
With the FormatDateTime() function, you can do
this:
<b><%= FormatDateTime(Date, 1)
%></b> which would return this:
But you can't do this:
Wednesday,
January 1, 1999
If limitations 1 or 2 are a major hang up for
you, you'll need to use different ASP/VBScript techniques to add the date to
your page. I'll cover those in my next article!
Limitation 3: The time isn't necessarily
"their" time.
Limitation 3 is more of a by-product than a
limitation, but I figured I would keep the naming conventions the same for this
section. If you use the the FormatDateTime() function (or any other date related
function) on the server side, the date/time returned will be whatever the
server's date and time is, not your client's time from their system.
If you want to ensure that the date and/or time a
visitor sees on your page is the date in their part of the coutry or world, then
consider using client side VBScript as an Internet Explorer only solution, or
switch to client side JavaScript for a universal browser solution.
Limitation 4: It's static.
Think of the displayed date or time as a
"snap shot" of when the page was requested by the visitor. You cant
use this function to display a "clock" that updates every second, or
automatically update the date on the page when one day turns to the next.
If you wanted to display a dynamic clock on your
page, you would need to use client side JavaScript, or VBScript (IE only) to
handle that task.
I hope you've enjoyed this article on the
FormatDateTime() function. I'll be back soon with more date and time related ASP
fun! If you have any questions or comments, send me an Email at: tony@southbaywebdesigns.com
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