Building asp pages

Building ASP Pages

Although these topics introduce some scripting and programming concepts, they are not intended to teach you a scripting language. Microsoft scripting languages (Microsoft VBScript and Microsoft JScript) provide their own documentation, and many additional scripting books are available from your local bookseller. So, if you are new to scripting, take advantage of the many books, classes, and Internet resources which can help you to master these languages.

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  Creating an ASP Page: Describes an ASP file and explains how to add script commands to a page.
  
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  Working with Scripting Languages: Explains how to set the primary language and how to use VBScript and JScript in server scripts.
  
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  Using Variables and Constants: Provides an introduction to using variables in ASP scripts and explains how to access constant definitions.
  
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  Interacting with Client-Side Scripts: Shows how to write server-side scripts that create and interact with client-side scripts.
  
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  Writing Procedures: Describes how to define procedures (functions and subroutines) and call them from server-side scripts.
  
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  Working with Collections: Describes how to access items in a built-in object's collections, including access by iterating through a collection.
  
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  Processing User Input: Explains how to collect and process information gathered from an HTML form.
  
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  Using Components and Objects: Explains how to create an instance of an object provided by a COM component, how to use the ASP built-in objects, and how to use the methods and properties of any object.
  
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  Setting Object Scope: Demonstrates the scope, or extent, of an object and describes how to create session and application scoped objects.
  
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  Sending Content to the Browser: Describes how to control the ways in which pages are sent to a browser.
  
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  Including Files: Explains how to use the #include statement to insert the contents of a file into an .asp file.
  
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  Managing Sessions: Describes how to preserve information about a user.
  
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  Accessing a Data Source: Explains how to use ASP and Microsoft ActiveX Data Objects (ADO) to retrieve information from a database.
  
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  Understanding Transactions: Demonstrates how to run a script under a transaction context. Business and credit card applications often need to the ability to run scripts and components within transactions.
  
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  Debugging ASP Scripts: Describes how to use the Microsoft Script Debugger to find and eliminate errors in your scripts.
  
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  Built-in ASP Objects: Provides a quick overview of the ASP built-in objects, and links to more detailed information.
  
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  Active Server Pages Objects Quick Reference Card: Contains quick reference information about ASP built-in objects.
  

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  Developing programmatically advanced collections of scripts called applications; see Developing Web Applications.
  
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  Designing Web applications; see Design Decisions.
  

Creating an ASP Page

An Active Server Pages (ASP) file is a text file with the extension .asp that contains any combination of the following:

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  Text
  
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  HTML tags
  
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  Server-side scripts
  

A quick way to create an .asp file is to rename your HTML files by replacing the existing .htm or .html file name extension with an .asp extension. If your file does not contain any ASP functionality, then the server dispenses with the ASP script processing and efficiently sends the file to the client. As a Web developer, this affords you tremendous flexibility because you can assign your files .asp extensions, even if you do not plan on adding ASP functionality until later.

To publish an .asp file on the Web, save the new file in a virtual directory on your Web site (be sure that the directory has Script or Execute permission enabled). Next, request the file with your browser by typing in the file's URL. (Remember, ASP pages must be served, so you cannot request an .asp file by typing in its physical path.) After the file loads in your browser, you will notice that the server has returned an HTML page. This may seem strange at first, but remember that the server parses and executes all ASP server-side scripts prior to sending the file. The user will always receive standard HTML.

You can use any text editor to create .asp files. As you progress, you may find it more productive to use an editor with enhanced support for ASP, such as Microsoft® Visual InterDev™. (For more information, visit the Microsoft Visual InterDev Web site at http://msdn.microsoft.com/vinterdev/.)

Adding Server-Side Script Commands

A server-side script is a series of instructions used to sequentially issue commands to the Web server. (If you have developed Web sites previously, then you are probably familiar with client-side scripts, which run on the Web browser.) In .asp files, scripts are differentiated from text and HTML by delimiters. A delimiter is a character or sequence of characters that marks the beginning or end of a unit. In the case of HTML, these delimiters are the less than (<) and greater than (>) symbols, which enclose HTML tags.

ASP uses the delimiters <% and %> to enclose script commands. Within the delimiters, you can include any command that is valid for the scripting language you are using. The following example shows a simple HTML page that contains a script command:

This page was last refreshed on <%= Now() %>.

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