XHTML forms provide a way for users to interact with Web pages. A form is, basically, a
data capture device. It presents the user with one or more data input or selection controls,
or fields, through which the user submits information to a Web page. On the basis of this
submitted information, the page can respond to the user. This response can vary depending on
the purpose of the form. The submitted data may be used
to direct visitors to a different page, much like what happens when clicking a link;
to present visitors with personalized pages containing information and links pertinent
to their interests or preferences;
to trigger a complex search process to locate information, products, or services about
which the user is interested;
to perform personalized displays of options or calculations of prices of those products
to trigger a credit card check during purchase of products or services;
to interface with the organization's accounting and billing systems to finalize purchase;
to generate automated email responses as purchase confirmations;
and the list can go on and on. The point is that forms are the triggers for a whole host of
activities that transform Web sites from simple electronic "page turners" into full-featured
information processing systems.
Forms gather information from users by displaying special form fields, or form controls, that
permit the user to enter data or make selections. The variety of standard controls that can be coded
on a Web form are shown below.
Note that there are three basic categories of controls. The fields labeled "Text Box,"
"Password," and "Textarea" present input areas where the user can enter information as
typed characters. The controls labeled "Radio Button," "Checkbox," and "Drop-down List"
provide options for the user to select from displayed items. The controls labeled
"Submit Button," "Submit Graphic," and "Reset Button" are clickable controls for submitting the
form data for processing or refreshing the entire form. On the following pages we'll take a
look at the uses and coding for each of these controls.
Of course, a single Web page containing a form cannot provide much in the way of processing
power. Usually, XHTML forms are backed by processing routines, or programs, run either locally
on the browser or remotely at the server, to handle data submitted from these forms. Thus, a form
by itself is not of much value unless supported by browser-side or server-side processing.
Processing routines can be included on the same Web page as the form and run by the browser.
of the features of regular programming languages. Its processing capabilities, though, are limited
to what can be achieved on the local desktop PC.
Most likely, form information is sent to the Web server where it is processed by programs written
in standard languages such as Visual Basic or Java. These are full-featured programming languages
that often interact with databases and files on the server, thus offering a full range of information
In this tutorial, focus is only on setting up forms on a Web page -- how to create the input,
selection, and submission controls. Browser or server processing is beyond the scope of interest.