Back to Basics: VBScript for ASP
February 5, 2001
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Interested in making ASP pages but do not know where to start?
Learning VBScript for ASP is half the battle, check out this
article to become in the know!
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Introduction
I have recently received a lot of e-mails from people who
understand the concepts of
Active Server Pages (ASP)
and the techniques discussed in other tutorials, but are getting
hung up on the code. What is worse is that I almost always hear
that novice ASP developers can never find resources that are
simple, easy to read, and for the "just getting my feet wet"
crowd. Let's face it, there are plenty of advanced resources out
there, so I have decided that it is time to go back to the basics
and help out those who would love to use ASP but have no idea
where to begin. Welcome to VBScript 101!
VBScript
is the heart of ASP. It is the scripting language that
ASP defaults to and is the language I recommend that you use for
all your ASP development. You can use server-side
JScript,
but there is no real advantage to doing so. Meanwhile, a big
disadvantage is that the ASP community has pretty much
standardized on VBScript. Most of the tutorials you see around
the Net and in books will not even mention JScript, other then in
passing. This article is going to give you a very basic
understanding of using VBScript in an ASP page. Please note that
this article is not going to teach you how to use VBScript
to do client-side
operations. Of course, there will be more overlap then not, but
the intent of this article is focused on using VBScript for ASP,
which should be why you are reading it the first place!
Scripting - What is It?
The big question — just what is a scripting and why should you
care? Not only is it a big question, it is a good question! In
very unacademic and somewhat nebulous terms, scripting is writing
code that is not compiled before it is run. What does that mean?
It means that unlike your standard
C++
or Visual Basic
type code, scripting languages like
Perl,
VBScript, JavaScript/JScript,
and others, do not have to be run through a compiler (something
that translates our human-readable code into code the machine can
understand) to be executed or run. Scripting code is interpreted,
or "compiled on the fly" so to speak. For instance, when you run
a Perl script in a CGI-BIN directory, the script is "interpreted"
by the perl "interpreter" and the results are posted back per
your instructions. VBScript (which stands for Visual Basic
Script) works pretty much the same way except it takes its syntax
base from its parent language — the full blown and compiler
dependent Visual Basic. And if you are smart, you would guess
that JavaScript and JScript work the same way, originally
inheriting their syntax base from Sun's
Java
(and more recently the standards set by
ECMAScript).
Let's look at a simple client-side JavaScript as an illustrative
example. Pretend you have a nice HTML page with the following
JavaScript in the heading.
<script language="JavaScript1.2" type="text/css">
<!-- //hide from older browsers
document.write('Hello Web World');
//-->
</script>
This tiny script will write "Hello Web World" on the top of the
page when a user visits it. Rather then being compiled, stored
and run as an executable every time a visitor hits, JavaScript
(or other scripting languages) enables you to embed commands into
the actual HTML that are "freshly" executed each time the page is
requested. Line-by-line the code is "interpreted" and the results
are, for all intents and purposes, instantaneous. One thing to
note about client-side scripting is that performance is largely
dependent on the client's hardware, software and connection
speed. When we get into VBScript for ASP, we will be dealing with
server-side
scripting, so performance will be a function of the
Web server we are using. For most of you it will still be your
own machine!
Which leads me to a very important thing you need to know about
VBScript for ASP. You need somewhere to test your code since it
will not function client-side. That is where Internet Information
Services (IIS) or Personal Web Server (PWS) come in. If you do
not have a hosting agreement with some third-party Web host that
supports ASP, you will need to configure your own PC or laptop to
act as the Web server. You can do this by downloading
Personal Web Server for Windows 9x
or by using IIS for NT4 (can be installed with the Option Pack) and Windows
2000 (comes on the CD). These two Web servers will configure
your system to have a directory on your C drive called InetPub.
Underneath InetPub will be a directly called wwwroot. This
directory is where you will want to store all your ASP pages. To
access and test your pages you will need to point your Web
browser to http://127.0.0.1/nameoffile.asp or to
http://localhost/nameoffile.asp; then you are all set!
Finally, when you are testing the code illustrated below, make
sure you put it in between ASP's <% '...lines and lines
of vbscript... %> server-side tags. These tell the server
that it should interpret the code inbetween. If you want to see
the value of any variables on screen when you are testing, use
<%= nameOfVariable %> and it will be displayed
in your browser.
VBScript - The Easy Stuff - Page 2
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