This column is intended to bring users' attention to the value of employing Windows NT server technology within their institution. This issue covers Active Server Pages (ASP) - one of the most useful benefits of having a Windows NT based web server.
Most web developers will encounter ASP through its inclusion with Microsoft's Internet Information Server  - the most popular Windows NT web server software. Internet Information Server is free, although you have to purchase a licence for Windows NT Server. However, ASP is by no means confined to Microsoft web servers or operating systems; a product from Chili!Soft  called Chili!ASP allows ASP to be run in a variety of non-Microsoft environments.
ASP pages are HTML documents that usually have a .asp file extension, and have server-side scripting nested around the HTML source. When an ASP document is requested from the server, the ASP scripting is interpreted, and the script output, together with the HTML contained within the document, are sent to the client's browser. This makes ASP similar to PHP3 , or, to some extent, the Server-Side Includes that are a feature of most web servers. ASP commands are usually inserted in the HTML markup between <%%> tags. So a basic ASP-enabled web page might look like this:
<TITLE>A simple ASP web page</TITLE>
<%Response.Write("<H1><FONT COLOR=red>Hello World!</FONT></H1>")%>
Figure 1: The simple ASP web page as displayed in a web browser
The advantage of using embedded scripting is that you can write the embedded ASP code in the HTML editing mode of your website creation application, then switch to a WYSIWYG page layout view in order to work on the appearance of the page. FrontPage 98 is one such application that allows easy switching between the WYSIWYG and HTML source view, and as long as you are aware of its idiosyncrasies, it won't mess up your ASP scripting. Alternatively, Visual InterDev  or EasyASP  are two specialised ASP editors that are worth considering.
Figure 2: Visual InterDev 6 is a specialised ASP editor
Out of the box, ASP contains six objects that can be referenced in web pages:
A common use of ASP is to link websites to other applications or services. This is usually achieved through the use of server components. Components can be rapidly created using a programming language such as Microsoft's Visual Basic. Alternatively, there are plenty of existing components that can be used. To get you started, Internet Information Server comes with a few - these can be used for database access, content rotation, finding client browser capabilities etc. Alternatively, a wide variety of 3rd party components are available , many of which have been released as freeware.
One area where ASP is particularly strong is in the area of database connectivity. The ability of Internet Information Server to link a website to any ODBC compliant database (and this includes Microsoft Access and SQL Server databases) through the use of a server component is arguably the most desirable feature of ASP. The feature is particularly welcome, given the strong rise in demand for database driven Intranet and Internet sites.
It is also possible to use server components to connect ASP to Exchange Server. The Outlook Web Access supplied with Microsoft Exchange Server uses ASP to create a completely web-based version of Outlook 98:
Figure 3: Outlook Web Access - a sophisticated web application that makes extensive use of ASP
There is an abundance of great resources for ASP developers, and the online ASP community is flourishing. The following websites are good starting places: 15 Seconds , activeserverpages.com , and the ASP Alliance . Wrox Press Inc.  publish some of the best printed books about ASP. Some of their recent offerings (, ) cover emerging technologies, such as combining ASP with the Active Directory Services Interfaces .
The web has always allowed the use of server-side scripts or executable files to provide the ability to extend the functionality of websites. Although some impressive applications can be created this way, development times can be long, and a great deal of technical expertise is required. By contrast, ASP has two major advantages over these development schemes; speed of development and ease of use. By basing ASP on VBScript, Microsoft has opened up the world of server-side web development to the millions of Visual Basic developers out there.
One major downside with ASP is that specialist ASP developers are hard to come by, and for many Unix/Linux experts, adjusting to Windows NT systems can be problematic. That said, ASP documentation is excellent, and in my opinion is far better than anything written about creating server-side scripts using Perl on Unix systems.
A few people are also sceptical about the abilities of ASP. But the fact that ASP is now used on plenty of high profile websites should give people confidence to use ASP within their institution. Examples of ASP users include Microsoft (www.microsoft.com), Tesco (www.tesco.co.uk), Compaq (www.compaq.com) and UEFA (www.uefa.com).
At Essex in particular, ASP technology is proving to be an essential tool to have in the web technology toolbox. Several of our users are starting to explore the potential of directly linking databases to the web, and ASP is proving to be invaluable in the provision of facilities to link databases to the web.
Current uses for ASP at Essex include*:
* Many of these examples are on "Intranet" sites that have access restrictions - contact me if you are interested in viewing such examples.
Some future uses that have been discussed:
University of Essex
Essex, CO4 3SQ