JavaScript® Bible, Sixth Edition

Chapter 21. The Form and Related Objects

IN THIS CHAPTER

• The form object as a container of form controls

• Processing form validations

• label, fieldset, and legend element objects

• Putting Web Forms 2.0 to work

Prior to the advent of dynamic object models and automatic page reflow, the majority of scripting in an HTML document took place in and around forms. Even with all the modern DHTML powers, forms remain the primary user interface elements of HTML documents because they enable users to input information and make choices in very familiar user interface elements, such as buttons, option lists, and so on.

Expanded object models of W3C-compatible browsers include scriptable access to form-related elements that are part of the HTML 4.0 specification. One pair of elements, fieldset and legend, provides both contextual and visual containment of form controls in a document. Another element, label, provides context for text labels that usually appear adjacent to form controls. Although there is generally little reason to script these objects, the browsers give you access to them just as they do for virtually every HTML element supported by the browser.

An interesting new twist in the form equation is Web Forms 2.0, which is a dramatically improved form technology based upon the original form features in HTML 4.0. Web Forms 2.0 establishes a powerful and consistent set of form controls that include built-in validation and much needed standard controls such as an interactive date picker, among other ...