Overview
These extensions are meant to extend CSS1 beyond its initial capabilities.
CSS1 addressed only the graphical behaviors used for screen rendering, but
it is expected that specifying rendering informationfor other mediums will
become an increasing need.
CSS Extension Proposals
CSS Positioning
Description:
This proposal extends CSS to support the precise, pixel level
positioning and visibility of HTML elements in three-dimensional
space.
Browser Support:
This proposal already is supported in both Internet Explorer 4.0 and
Netscape 4.0.
CSS Printing
Description:
Printing HTML documents has been problematic in the past because
the static, paged nature of the printed page disagrees fundamentally
with screen rendered implementations. The printing extensions for CSS
will allow attachment of properties that give more formatting cues to a
print rendering device. These extensions let style sheets express page
breaks, page boxes, and media dependencies. A method of pointing to
alternate versions (possibly more print-friendly) of a document is described.
Browser Support:
Internet Explorer does not yet support these extensions in the 4.0 version
of its browser, but there is the possibility that some of these properties
may be supported in its final release.
Aural CSS
Description:
Aural CSS allows the attachment of audio presentation properties
to HTML documents without having to create multiple documents or using
extra markup. Speech rendering is currently used by the vision and print
impaired communities using a combination of speech synthesis and 'audio
icons', but the current process usually only uses pages that are
converted to plain text and fed to a 'screen reader'. Aural CSS allows the
attachment of properties controlling such speech factors as pitch, volume,
pause control and spatial audio qualities which can greatly enrich the aural
presentation of a page.
While the pressing need for these extensions is felt most strongly in the
disabled community, other non-visual presentation methods (including car
and telephone browsing) are becoming important as delivery platforms for
content as well and will benefit greatly from these additional properties.
Browser Support:
Currently, only the Emacs W3 browser can support these CSS properties
via special extensions created by T.V. Raman of Adobe. It is unknown
how widely these properties will be supported by common browsers in the future.