Developing Web Applications

Factoring Your Application

A Web application is a hierarchy of interdependent pages, each one representing a distinct stage of the application. Web applications map an ordered sequence of input events to a corresponding sequence of output events, using a finite number of elements.

Most Web applications make use of (or should make use of) the following: content, hyperlinks, forms, components, server-side actions, redirection, and loops.

Content Content—information presented in the form of text, graphics, or even music or video files—is the most common element in most Web applications. Content can be presented on static HTML pages or be dynamically generated by an ASP page. Content elements usually have one well-defined entry point with links to other pages.
Hyperlinks The primary purpose of hyperlinks is to facilitate movement to other pages or parts of the same page. Site maps, toolbars, HREFs, anchors, form buttons, and navigational controls are all examples of hyperlinks. These elements often appear in their own browser frame and control the navigation throughout the site. They can also appear as a separate index page or table of contents, which is replaced once a link is selected. Hyperlinks represent a user choice, very much like a menu option does in a stand-alone application.
Forms Forms are used to collect information from the user. Depending on how a form is designed, its outcome might change once it is submitted, as a function of user input. Forms can be chained together consecutively to create “Form wizards.” Client-side or server-side actions usually process these forms.
Components A component is any code-level unit providing a relatively independent piece of logic that can be used either separately or in combination with other components throughout the application. The level of granularity and scope of responsibility distinguishes components from other application elements. Components can generate content or provide server-side logic.
Action Action in this case means how an application responds to user action. When the user submits a form, for example, the application processes the form. Action pages perform business logic, such as data entry, calculations, or administrative functions. Action (processing) can occur both on the server and on the client, and can be used to generate content such as confirmation or error messages.
Redirection A redirection page or script can perform logic to branch the flow of the application. Although it doesn’t actually perform a redirect, a page containing a frameset can also be considered a redirection page, since it causes other pages to load. Redirection is usually more adaptable and flexible if implemented as a separate ASP page.
Loops Loop pages are ASP pages that refer to themselves in order to present different content, depending on user input. For example, a page might select content based on which browser is being used.

You can create a huge variety of complex applications using the elements just described in this list.