HTML and CSS Reference
In-Depth Information
CSS Version
Specification URL
Description
CSS1
www.w3.org/TR/REC-CSS1//
Classic CSS implementation that
introduced text, list, box, margin, border,
color, and background properties. Initially
defined in 1996, most every feature of
CSS1 is supported in Web browsers,
but small quirks do exist around some
lesser-used features like white-space,
letter-spacing, display, and others. Some
problems with CSS1 support are more
significant in older, pre-Internet Explorer 7
browsers.
CSS2
www.w3.org/TR/1998/REC-CSS2-19980512/ Specification that is primarily known for
positioning and media, particularly print
style sheet features. Many aspects of
CSS2, such as aural style sheets, were
never widely implemented and were
removed in the later revision of this level
of CSS.
CSS 2.1
www.w3.org/TR/CSS21/
A revision of the CSS2 specification
that makes some corrections and is
normalized to more clearly represent what
most browser vendors have implemented.
Note that many CSS2 features removed
from this specification are found in
CSS3 modules. This is currently the
recommended CSS specification for
study and use.
CSS3
www.w3.org/Style/CSS/current-work#CSS3
Modularized specification of CSS. Various
modules extend and improve aspects
of previous CSS versions; for example,
the CSS3 Color module addresses color
correction, transparency, and more, while
the CSS3 Fonts module addresses features
to add effects to fonts, adjust their display,
and even download custom fonts. Some
modules are all new, like the Transitions
and Animations modules. In either the
improved or new feature situation, based
upon implementation and specification
maturation rates, readers are encouraged
to check the CSS3 Web site and test well,
because few features are likely to be cross
browser.
T
ABLE
5-1
Description of Common CSS Versions
