The Web’s origins lie in linked static content, and many sites today remain static: That is, you must explicitly modify your HTML pages in order for the content your Web server sends to a client browser to change. In the static model, a client browser uses the Hypertext Transport Protocol (HTTP) to request an HTML page from the Web server. A server receives the request and sends the HTML page back to the client browser, which formats and displays the page. Although this model provides instant access to nicely formatted pages of information for your employees or potential customers, it provides only limited interaction between the user and the Web server. And the information is only as current as the last time someone manually edited the files.
Note Although HTTP browsers and servers can transfer data formats other than HTML, such as Audio Video Interleaved (AVI) and Virtual Reality Markup Language (VRML), for the sake of simplicity, most of the discussion in this guide refers to content simply as HTML.
With Common Gateway Interface (CGI), Internet Server Application Programming Interface (ISAPI), and other gateway interfaces, a user can send an HTTP request to an executable application rather than requesting a static HTML file. The server immediately runs the specified program. The program can read environment variables and standard input to determine what values were passed with the request; for example, values that a user inputs by filling out an HTML form. The program then parses the values for meaningful information, and generates output in HTML to send back to the client. The disadvantage of gateway programs, however, is that they are difficult to create and change. And they require an entirely different design process than HTML pages do.
ASP allows you to include executable script directly in your HTML content. ASP applications are:
What does this mean for you, the Web content provider? It means the difference between publishing content and providing interactive business applications. For example, a travel agency can go beyond just publishing flight schedules; it can use scripting to enable the customer to check available flights, compare fares, and reserve a seat on a flight.
ASP applications are easy to develop because you use ASP scripting to develop them. With ASP scripting, you can use various scripting languages, including Microsoft® Visual Basic® Scripting Edition (VBScript) and JScript. Active Server Pages Tutorial offers a hands-on introduction to ASP scripting.
ASP scripting integrates the scripting process directly with the information and appearance you want to display for the user. HTML development and scripting development become the same process, enabling you to focus directly on the look and feel of your Web pages, weaving dynamic elements into your pages as appropriate.
Writing ASP scripts is relatively easy, yet these scripts provide a powerful environment for your Internet and intranet presence. You can incorporate sophisticated functionality by using ASP components. You can use these components, formerly known as OLE Automation servers, to process data and generate useful information.
ActiveX technology pushes forward on the smart server front, making the development of rich server applications easier, especially for the Webmaster, VBScript author, Microsoft® Access user, or Web content developer. ASP-generated content is compatible with all standard Web browsers.