csswg-drafts/css2/changes.src at 495b5f5b48d050534a58ad35ec96ca42cca66aae · w3c/csswg-drafts · GitHub

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html lang="en">
<!-- $Id: changes.src,v 2.5 1998-02-24 22:52:41 ijacobs Exp $ -->
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<TITLE>Appendix B: Changes from CSS1</TITLE>
</HEAD>
<BODY>
<H1 align="center">Changes from CSS1</H1>
<P><em>This appendix is informative, not normative.</em></P>

<P>CSS2 builds on CSS1 and all valid CSS1 style sheets are valid CSS2
style sheets. The changes between the CSS1 specification (see
[[CSS1]]) and this specification fall into three groups: new
functionality, updated descriptions of CSS1 functionality, and changes
to CSS1.

<H2>New functionality</H2>

<P>In addition to the functionality of CSS1, CSS2 supports:</p>

<UL>

<LI>The concept of <A HREF="media.html">media types</A>.

<LI><A HREF="page.html">Paged media</A>

<LI><A HREF="aural.html">Aural style sheets</A>

<LI><A HREF="fonts.html#font-selection">An extended font selection</A>
mechanism, including intelligent matching, synthesis, and downloadable
fonts. Also, the concept of system fonts has been is introduced, and a
new property, <span
class="propinst-font-size-adjust">'font-size-adjust'</span>, has been added.

<LI><A HREF="tables.html">Tables</A>, including new values on <span
class="propinst-display">'display'</span> and <span
class="propinst-vertical-align">'vertical-align'</span>.

<LI><A HREF="visuren.html#relative-positioning">Relative</A> and <A
HREF="visuren.html#absolute-positioning">Absolute positioning</A>,
including <A HREF="visuren.html#fixed-positioning">fixed positioning</A>.

<LI>An extended <A HREF="selector.html">selector</A> mechanism,
including child selectors, adjacent selectors and attribute selectors.

<LI><A HREF="generate.html#generated-text">Generated content and automatic
numbering</A>

<LI>Text shadows, through the new <LI><span
class="propinst-text-shadow">'text-shadow'</span> property.

<LI>A new <A HREF="selector.html#link-pseudo-classes">link
pseudo-class</A>, :hover.

<LI><A HREF="ui.html#system-colors">System colors</A>

</UL>


<H2>Updated descriptions</H2>

<P>The CSS1 specification was short and concise. This specification is
much more voluminous and more readable. Much of the additional content
describes new functionality, but the description of CSS1 features has
also been extended. Except in a few cases described below, the
rewritten descriptions do not indicate a change in syntax nor
semantics.

<!--
<UL>
<LI>recommends that the user preference is used as the initial value
</UL>
-->

<H2>Changes</H2>

<UL>

<LI>In CSS2 <A HREF="syndata.html#color-units">color values</A> are clipped
with regard to the device gamut, not with regard to the sRGB gamut as
in CSS1.

<LI>[strength of constraints based on writing direction]

<!-- Don't forget -IJ -->

<LI>In CSS1, several properties (e.g., 'padding') had values referring
to the width of the parent element. This was an error; the value
should always refer to the width of a block-level element and this
specification reflects this by introducing the term "containing block".

<LI>Initial value of 'display' is 'inline', not 'block' as in CSS1.

<LI>The 'clear' property now only applies to block-level elements.

<!-- Is the 'clear' comment final? -IJ -->

<li>Please also consult the section on the <a
href="grammar.html#tokenizer-diffs">differences between the CSS1
and CSS2 tokenizer</a>.
</UL>

</BODY>
</HTML>