Introduction

This section is normative.

CSS3 is a set of modules, divided up and profiled in order to simplify the specification, and to allow implementors the flexibility of supporting the particular modules appropriate for their implementations.

This module describes selectors and CSS properties which enable authors to style user interface related states, element fragments, properties and values.

Section 2.1 of CSS1 [CSS1] and Chapter 18 of CSS2 [CSS2] introduced several user interface related pseudo- classes, properties and values. Section 6.6.4 of Selectors HYPERLINK \l "page1" [SELECT] also describes several additional user interface related pseudo-classes (and one pseudo-element).

This Working Draft extends them to provide the ability, through CSS, to style elements based upon additional user interface states, to style fragments of user interface elements, and to alter the dynamic presentation of elements in ways previously only available through specific HTML4/XHTML1 elements and attributes.



1.1. Purpose

The purpose of this specification is to achieve the following objectives:

● Extend the user interface features in CSS2.1.

● Provide additional CSS mechanisms to simulate the appearance of various standard form elements.

● Provide additional CSS mechanisms to augment or replace other dynamic presentation related features in HTML4/XHTML1.

● Introduce directional navigation properties to assist in the construction of user interfaces which make use of a directional navigation model.

● Introduce properties and values to specify icon presentations for elements to enhance accessibility


1.2. Scope

This proposal specifies how to alter the look and feel of various elements, and specifically does not address the meaning behind what a specific look and feel may imply. For example, with the additions in the proposal, an author can make any element look and even feel like a submit button. Yet, that arbitrary element is not afforded any additional meaning, so pushing it does nothing by default, and certainly does not submit a form.

Similarly, the HTML4 ) could be styled to appear as a group of radio-buttons, and yet, since those elements are still semantic checkboxes, they can still be individually checked or unchecked, rather than acquiring any kind of radio-button group semantic where only one can be checked.

Each example of presentation has a different look and feel, but maintains its original meaning, a choice (or choices) among several alternatives. This proposal addresses only the former (look and feel), not the latter (meaning).

Since this proposal serves to simulate the appearance of various user interface and forms elements in HTML4/XHTML, it is perhaps useful to call out what specifically is believed to be outside the scope of CSS, or better suited to document structure rather than style and therefore not addressed by this proposal:

● Form semantics, including, but not limited to, submission, resetting, naming, what determines a successful or valid form control, and how to process form data.

● Form contents, including, but not limited to initial value, current value, and form content types. The HTML4 'maxlength' attribute, for example, determines the maximum number of characters the user can enter into an or field, and as such is a content constraint rather than a presentational suggestion.

● Form control dependencies, including, but not limited to, whether only one option from a set of choices may be chosen, or whether multiple options may be chosen.
● The HTML4/XHTML1

element and its unique attributes ('action', 'method', 'enctype', 'acce

'accept-charset').

In addition, this document does not attempt to solve all user interface related issues / features that can be found in modern user interfaces. Perhaps future versions may attempt to solve these. For example:

● Complex or composite controls (e.g. the HTML4 and the elements).

● The appearance, styling and coloring of scrollbars.

● Window layering. There is no attempt made to distinguish the appearance of elements in the front-most window versus non-front-most windows. The semantics of window layering must be addressed before it is appropriate to attempt to style such concepts.

● Palettes and floating windows. Along with the concept of "frontmost" window, windows that float but do not receive focus are also not addressed.

● Browser window chrome and toolbars.

● The default styling of the HTML4/XHTML1

,

, <'frame> and <'frameset> elements.

● Frame-resizing behavior. The behavior of <'frame> and <'frameset>, specifically the ability to "share" resizability when elements share a border, perhaps by leveraging the border-collapse property is also not addressed.

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