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<!DOCTYPE html>
<html>
<head>
<title>CSS Lists and Counters Module Level 3</title>
<meta content="text/html; charset=utf-8" http-equiv=Content-Type>
<link href="http://dev.w3.org/csswg/default.css" rel=stylesheet
type="text/css">
<style>
p { text-indent: 0 !important; margin: .5em 0; }
code.inline { white-space: nowrap; }
.alphabetic-example { font-family: monospace; font-size: 90%; margin: 1em 0 1em 2em; }
.alphabetic-example > span { display: inline-block; width: 50px;}
.alphabetic-example > span > img { width: 16px; height: 16px; }
pre > code { white-space: pre-wrap; }
</style>
<link href="http://www.w3.org/StyleSheets/TR/W3C-ED" rel=stylesheet
type="text/css">
<body>
<div class=head> <!--begin-logo-->
<p><a href="http://www.w3.org/"><img alt=W3C height=48
src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->
<h1>CSS Lists and Counters Module Level 3</h1>
<h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 9 July 2011</h2>
<dl>
<dt>This version:
<dd><!--<a href="http://www.w3.org/TR/2011/WD-css3-lists-20110709">http://www.w3.org/TR/2011/WD-css3-lists-20110709</a></dd>-->
<a
href="http://dev.w3.org/csswg/css3-lists/">http://dev.w3.org/csswg/css3-lists/</a>
<dt>Latest version:
<dd><a
href="http://www.w3.org/TR/css3-lists/">http://www.w3.org/TR/css3-lists/</a>
<dt>Previous version:
<dd><a
href="http://www.w3.org/TR/2002/WD-css3-lists-20021107/">http://www.w3.org/TR/2002/WD-css3-lists-20021107/</a>
<dt>Editor:
<dd><a href="http://www.xanthir.com/contact">Tab Atkins Jr.</a>, Google
Inc.
<dt>Previous Editors:</dt>
<!-- in the order tantek requested -->
<dd>Ian Hickson, <a href="mailto:ian@hixie.ch">ian@hixie.ch</a>
<dd><span lang=tr>Tantek Çelı̇k</span>, Microsoft
Corporation, <a
href="mailto:tantekc@microsoft.com">tantekc@microsoft.com</a>
<dt>Contributors:</dt>
<!-- in order of volume of input -->
<dd>Simon Montagu, AOL-TW/Netscape, <a
href="mailto:smontagu@netscape.com">smontagu@netscape.com</a>
<dd>Daniel Yacob, <a href="mailto:yacob@geez.org">yacob@geez.org</a>
<dd>Christopher Hoess, <a
href="mailto:choess@stwing.upenn.edu">choess@stwing.upenn.edu</a>
<dd>Daniel Glazman, AOL-TW/Netscape, <a
href="mailto:glazman@netscape.com">glazman@netscape.com</a>
</dl>
<!--begin-copyright-->
<p class=copyright><a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
rel=license>Copyright</a> © 2011 <a
href="http://www.w3.org/"><acronym title="World Wide Web
Consortium">W3C</acronym></a><sup>®</sup> (<a
href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute
of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym
title="European Research Consortium for Informatics and
Mathematics">ERCIM</acronym></a>, <a
href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
<a
href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
and <a
href="http://www.w3.org/Consortium/Legal/copyright-documents">document
use</a> rules apply.</p>
<!--end-copyright-->
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc" id=abstract> Abstract</h2>
<p>CSS is a language for describing the rendering of structured documents
(such as HTML and XML) on screen, on paper, in speech, etc. This draft
contains the features of CSS level 3 relating to list styling. It
includes and extends the functionality of CSS level 2 <a
href="#CSS21" rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>, which builds
on CSS level 1 <a href="#CSS1"
rel=biblioentry>[CSS1]<!--{{CSS1}}--></a>. The main extensions compared to
level 2 are a pseudo-element representing the list marker, and a
method for authors to define their own list-styles.
<h2 class="no-num no-toc" id=status> Status of this document</h2>
<!--begin-status-->
<p>This is a public copy of the editors' draft. It is provided for
discussion only and may change at any moment. Its publication here does
not imply endorsement of its contents by W3C. Don't cite this document
other than as work in progress.
<p>The (<a
href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
mailing list <a
href="mailto:www-style@w3.org?Subject=%5Bcss3-lists%5D%20PUT%20SUBJECT%20HERE">
www-style@w3.org</a> (see <a
href="http://www.w3.org/Mail/Request">instructions</a>) is preferred for
discussion of this specification. When sending e-mail, please put the text
“css3-lists” in the subject, preferably like this:
“[<!---->css3-lists<!---->] <em>…summary of
comment…</em>”
<p>This document was produced by the <a href="/Style/CSS/members">CSS
Working Group</a> (part of the <a href="/Style/">Style Activity</a>).
<p>This document was produced by a group operating under the <a
href="/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent
Policy</a>. W3C maintains a <a href="/2004/01/pp-impl/32061/status"
rel=disclosure>public list of any patent disclosures</a> made in
connection with the deliverables of the group; that page also includes
instructions for disclosing a patent. An individual who has actual
knowledge of a patent which the individual believes contains <a
href="/Consortium/Patent-Policy-20040205/#def-essential">Essential
Claim(s)</a> must disclose the information in accordance with <a
href="/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the
W3C Patent Policy</a>.</p>
<!--end-status-->
<h2 class="no-num no-toc" id=contents> Table of contents</h2>
<!--begin-toc-->
<ul class=toc>
<li><a href="#introduction"><span class=secno>1. </span> Introduction</a>
<li><a href="#declaring-a-list-item"><span class=secno>2. </span>
Declaring a List Item</a>
<li><a href="#marker-content"><span class=secno>3. </span> Marker Content:
The ‘<code class=property>list-style-type</code>’ and
‘<code class=property>list-style-image</code>’ properties</a>
<li><a href="#list-style-position-property"><span class=secno>4. </span>
Marker Position: The ‘<code
class=property>list-style-position</code>’ property</a>
<li><a href="#list-style-property"><span class=secno>5. </span> The
‘<code class=property>list-style</code>’ shorthand
property</a>
<li><a href="#marker-pseudoelement"><span class=secno>6. </span> Markers:
The ‘<code class=css>::marker</code>’ pseudo-element</a>
<ul class=toc>
<li><a href="#content-property"><span class=secno>6.1. </span>
Generating the computed value of the ‘<code
class=property>content</code>’ property</a>
</ul>
<li><a href="#display-marker"><span class=secno>7. </span> Positioning
Markers: the ‘<code class=css>marker</code>’ value for
‘<code class=property>position</code>’</a>
<li><a href="#counter-style"><span class=secno>8. </span> Defining Custom
Counter Styles: the ‘<code class=css>@counter-style</code>’
rule</a>
<ul class=toc>
<li><a href="#counter-style-type"><span class=secno>8.1. </span> Counter
algorithms: the ‘<code class=property>type</code>’
descriptor</a>
<ul class=toc>
<li><a href="#repeating"><span class=secno>8.1.1. </span>
repeating</a>
<li><a href="#numeric"><span class=secno>8.1.2. </span> numeric</a>
<li><a href="#alphabetic"><span class=secno>8.1.3. </span>
alphabetic</a>
<li><a href="#symbolic"><span class=secno>8.1.4. </span> symbolic</a>
<li><a href="#non-repeating"><span class=secno>8.1.5. </span>
non-repeating</a>
<li><a href="#additive"><span class=secno>8.1.6. </span> additive</a>
<li><a href="#override"><span class=secno>8.1.7. </span> override</a>
</ul>
<li><a href="#counter-style-negative"><span class=secno>8.2. </span>
Formatting negative values: the ‘<code
class=property>negative</code>’ descriptor</a>
<li><a href="#counter-style-prefix"><span class=secno>8.3. </span>
Symbols before the marker: the ‘<code
class=property>prefix</code>’ descriptor</a>
<li><a href="#counter-style-suffix"><span class=secno>8.4. </span>
Symbols after the marker: the ‘<code
class=property>suffix</code>’ descriptor</a>
<li><a href="#counter-style-range"><span class=secno>8.5. </span>
Limiting the counter scope: the ‘<code
class=property>range</code>’ descriptor</a>
<li><a href="#counter-style-fallback"><span class=secno>8.6. </span>
Defining fallback: the ‘<code
class=property>fallback</code>’ descriptor</a>
<li><a href="#counter-style-glyphs"><span class=secno>8.7. </span>
Marker characters: the ‘<code class=property>glyphs</code>’
and ‘<code class=property>additive-glyphs</code>’
descriptors</a>
</ul>
<li><a href="#ua-stylesheet"><span class=secno>9. </span> Predefined
Counter Styles</a>
<ul class=toc>
<li><a href="#predefined-repeating"><span class=secno>9.1. </span>
Predefined Repeating Styles</a>
<li><a href="#predefined-numeric"><span class=secno>9.2. </span>
Predefined Numeric Styles</a>
<li><a href="#predefined-alphabetic"><span class=secno>9.3. </span>
Predefined Alphabetic Styles</a>
<li><a href="#predefined-symbolic"><span class=secno>9.4. </span>
Predefined Symbolic Styles</a>
<li><a href="#predefined-non-repeating"><span class=secno>9.5. </span>
Predefined Non-Repeating Styles</a>
<li><a href="#predefined-additive"><span class=secno>9.6. </span>
Predefined Additive Styles</a>
</ul>
<li><a href="#predefined-counters"><span class=secno>10. </span> Complex
Counter Styles</a>
<ul class=toc>
<li><a href="#glyph-counters"><span class=secno>10.1. </span> Glyphs</a>
<li><a href="#ethiopic-numeric"><span class=secno>10.2. </span> The
‘<code class=property>ethiopic-numeric</code>’ counter
style</a>
<li><a href="#cjk-counter-styles"><span class=secno>10.3. </span> The
Chinese longhand counter styles</a>
</ul>
<li><a href="#optional-extensions"><span class=secno>11. </span> Optional
Extended Counter Styles</a>
<ul class=toc>
<li><a href="#extended-cjk-longhand"><span class=secno>11.1. </span>
Extended CJK Longhand</a>
<li><a href="#extended-numbered"><span class=secno>11.2. </span>
Extended Non-Repeating Numbered Styles</a>
</ul>
<li><a href="#html4"><span class=secno>12. </span> Sample style sheet for
HTML</a>
<li class=no-num><a href="#profiles"> Profiles</a>
<li class=no-num><a href="#acknowledgments"> Acknowledgments</a>
<li class=no-num><a href="#changes"> Changes From CSS2.1</a>
<li class=no-num><a href="#references">References</a>
<ul class=toc>
<li class=no-num><a href="#normative-references">Normative
references</a>
<li class=no-num><a href="#other-references">Other references</a>
</ul>
<li class=no-num><a href="#property-index">Property index</a>
<li class=no-num><a href="#index">Index</a>
</ul>
<!--end-toc-->
<hr>
<!-- ====================================================================== -->
<h2 id=introduction><span class=secno>1. </span> Introduction</h2>
<p>The list model in this module differs in some important ways from the
list model in CSS2, specifically in its handling of markers.
Implementation experience suggested the CSS2 model overloaded the ::before
and ::after pseudo-elements with too much behavior, while at the same time
introducing new properties when existing properties were sufficient.
<p>Most block-level elements in CSS generate one principal block box. In
this module, we discuss two CSS mechanisms that cause an element to have
an associated marker: one method associates one principal block box (for
the element's content) with a separate marker box (for decoration such as
a bullet, image, or number), and the other inserts a marker box into the
principal box. Unlike :before and :after content, the marker box cannot
affect the position of the principal box, whatever the positioning scheme.
<div class=html-example>
<p>For instance, the following example illustrates how markers may be used
to add parentheses around each numbered list item. This HTML application
and style sheet:</p>
<pre>
<!doctype html>
<html>
<head>
<title>Creating a list with markers</title>
<style>
li::marker { content: "(" counter(list-item, lower-roman) ")"; }
li { display: list-item; }
</style>
</head>
<body>
<ol>
<li>This is the first item.</li>
<li>This is the second item.</li>
<li>This is the third item.</li>
</ol>
</body>
</html>
</pre>
<p>should produce something like this:</p>
<pre>
(i) This is the first item.
(ii) This is the second item.
(iii) This is the third item.
</pre>
</div>
<p>With descendant selectors and child selectors, it's possible to specify
different marker types depending on the depth of embedded lists.
<p class=issue>A future release of this module will probably include ways
to render tree lists.</p>
<!-- ====================================================================== -->
<h2 id=declaring-a-list-item><span class=secno>2. </span> Declaring a List
Item</h2>
<p>To declare a <dfn id=list-item>list item</dfn>, the ‘<code
class=property>display</code>’ property must be set to ‘<code
class=css>list-item</code>’ or ‘<a
href="#inline-list-item"><code
class=css>inline-list-item</code></a>’ (defined later in this
section). This, in addition to generating a ‘<code
class=css>::marker</code>’ pseudo-element and enabling the
properties described below for that element, causes that element to
increment the list item counter ‘<code
class=css>list-item</code>’. (This does not affect the specified or
computed values of the counter properties.)
<p>The ‘<code class=css>list-item</code>’ counter is a real
counter, and can be directly affected using the ‘<code
class=property>counter-increment</code>’ and ‘<code
class=css>counter-reset</code>’ properties. It can also be used in
the ‘<code class=css>counter()</code>’ and ‘<code
class=css>counters()</code>’ functions.
<table class=propdef>
<tbody>
<tr>
<th>Property:
<td>‘<code class=property>display</code>’
<tr>
<th>New Value:
<td><dfn id=inline-list-item>inline-list-item</dfn>
<tr>
<th>Initial:
<td>same as CSS2.1
<tr>
<th>Applies to:
<td>same as CSS2.1
<tr>
<th>Inherited:
<td>same as CSS2.1
<tr>
<th>Percentages:
<td>same as CSS2.1
<tr>
<th>Media:
<td>same as CSS2.1
<tr>
<th>Computed value:
<td>same as CSS2.1
</table>
<p>The ‘<a href="#inline-list-item"><code
class=css>inline-list-item</code></a>’ display value makes the
element a list item, which means it can generate a ::marker
pseudo-element. The element also affects the predefined ‘<code
class=css>list-item</code>’ counter, as specified above. Otherwise,
this display value is treated identically to ‘<code
class=css>inline</code>’.
<p class=note>This display value is silly, and only necessary because we
haven't yet defined ‘<code class=property>display</code>’ to
be split into subproperties. When that happens, "being a list item" will
just be a property value that can apply to block, inline, and other
elements.</p>
<!-- ====================================================================== -->
<h2 id=marker-content><span class=secno>3. </span> Marker Content: The
‘<a href="#list-style-type"><code
class=property>list-style-type</code></a>’ and ‘<a
href="#list-style-image"><code
class=property>list-style-image</code></a>’ properties</h2>
<table class=propdef>
<tbody>
<tr>
<th>Name:
<td><dfn id=list-style-type>list-style-type</dfn>
<tr>
<th>Value:
<td><a href="#ltstring"><b><string></b></a> | <a
href="#ltcounter-style"><b><counter-style></b></a> | none
<tr>
<th>Initial:
<td>disc
<tr>
<th>Applies To:
<td><a href="#list-item"><i title="list item">list items</i></a>
<tr>
<th>Inherited:
<td>yes
<tr>
<th>Percentages:
<td>N/A
<tr>
<th>Media:
<td>visual
<tr>
<th>Computed Value:
<td>specified value
</table>
<p>When the ‘<a href="#list-style-image"><code
class=property>list-style-image</code></a>’ property is ‘<a
href="#none"><code class=css>none</code></a>’ or not a valid image,
the ‘<a href="#list-style-type"><code
class=property>list-style-type</code></a>’ property is instead used
to construct the default contents of a list item's marker.
<dl>
<dt><dfn id=ltstring><string></dfn>
<dd>The ‘<code class=css>::marker</code>’ pseudoelement must
use the provided string as its default contents.
<dt><dfn id=ltcounter-style><counter-style></dfn>
<dd>
<p>The ‘<code class=css>::marker</code>’ pseudoelement's
default contents must be the value of the ‘<code
class=css>list-item</code>’ counter, formatted according to the
given counter style. Algorithms for formatting a value according to a
counter style are given later in this spec.</p>
<p>This specification defines a method for authors to create their own
counter styles which may be used here. Additionally, many useful counter
styles are predefined in the sections on <a
href="#predefined-counters">Complex Counter Styles</a> and <a
href="#ua-stylesheet">Predefined Counter Styles</a>.</p>
<dt><dfn id=none>none</dfn>
<dd>The ‘<code class=css>::marker</code>’ pseudoelement must
have no default contents. This will suppress the creation of a marker
unless the ‘<code class=css>::marker</code>’ has its contents
specified directly through the ‘<code
class=property>content</code>’ property.
</dl>
<table class=propdef>
<tbody>
<tr>
<th>Name:
<td><dfn id=list-style-image>list-style-image</dfn>
<tr>
<th>Value:
<td><image> | none
<tr>
<th>Initial
<td>none
<tr>
<th>Applies To:
<td><a href="#list-item"><i title="list item">list items</i></a>
<tr>
<th>Inherited:
<td>yes
<tr>
<th>Percentages:
<td>N/A
<tr>
<th>Media:
<td>visual
<tr>
<th>Computed Value:
<td>
1EB4
specified value
</table>
<p>This property sets the image that will be used as the list item marker.
When the <b><image></b> resolves to a valid image, it is used as the
default contents of ‘<code class=css>::marker</code>’ instead
of the value specified by ‘<a href="#list-style-type"><code
class=property>list-style-type</code></a>’.
<p>If the value ‘<a href="#none"><code
class=css>none</code></a>’ is provided, or the <b><image></b>
doesn't resolve to a valid image, then the default contents are given by
‘<a href="#list-style-type"><code
class=property>list-style-type</code></a>’ instead.
<div class=example>
<p>The following example sets the marker at the beginning of each list
item to be the image "ellipse.png".</p>
<pre>LI { list-style-image: url("http://www.example.com/ellipse.png") }</pre>
</div>
<!-- ====================================================================== -->
<h2 id=list-style-position-property><span class=secno>4. </span> Marker
Position: The ‘<a href="#list-style-position"><code
class=property>list-style-position</code></a>’ property</h2>
<table class=propdef>
<tbody>
<tr>
<th>Name:
<td><dfn id=list-style-position>list-style-position</dfn>
<tr>
<th>Value:
<td>inside | outside
<tr>
<th>Initial:
<td>outside
<tr>
<th>Applies To:
<td><a href="#list-item"><i title="list item">list items</i></a>
<tr>
<th>Inherited:
<td>yes
<tr>
<th>Percentages:
<td>N/A
<tr>
<th>Media:
<td>visual
<tr>
<th>Computed Value:
<td>specified value
</table>
<p>This property specifies the position of the ‘<code
class=css>::marker</code>’ pseudo-element's box in the <a
href="#list-item"><i>list item</i></a>. Values have the following
meanings:
<dl>
<dt><dfn id=inside>inside</dfn>
<dd>The ‘<code class=css>::marker</code>’ pseudo-element is a
‘<code class=css>display:inline</code>’ element placed
immediately before the ‘<code class=css>::before</code>’
pseudo-element in the <a href="#list-item"><i>list
item</i></a>‘<code class=css>s principle box, after which the
element</code>’s content flows. Note that if there is no inline
content, this will create a line box, just as content in an inline
‘<code class=css>::before</code>’ pseudo-element would. Also
note that all the properties that apply to inline elements apply to the
‘<code class=css>::marker</code>’ pseudo-element in this
state, and this ‘<code class=css>::marker</code>’ box
participates in the inline box model in the normal manner.
<dt><dfn id=outside>outside</dfn>
<dd>As ‘<a href="#inside"><code class=css>inside</code></a>’,
plus the computed value of ‘<code
class=property>position</code>’ on the ::marker pseudo-element is
‘<code class=css>marker</code>’. The section on the new
‘<code class=property>marker</code>’ value for ‘<code
class=property>position</code>’ explains the consequences of this.
</dl>
<p>Note that a marker is only generated if the computed value of the
‘<code class=property>content</code>’ property for the
element's ‘<code class=css>::marker</code>’ pseudo-element is
not ‘<a href="#none"><code class=css>none</code></a>’.
<div class=example>
<p>For example:
<pre class=html-example>
<!doctype html>
<html>
<head>
<title>Comparison of inside/outside position</title>
<style>
ul { list-style: outside; }
ul.compact { list-style: inside; }
</style>
</head>
<body>
<ul>
<li>first list item comes first</li>
<li>second list item comes second</li>
</ul>
<ul class=compact>
<li>first list item comes first</li>
<li>second list item comes second</li>
</ul>
</body>
</html>
</pre>
<p>The above example may be formatted as:</p>
<div class=figure>
<p><img alt="list with bullets to the left of it and list with bullets
inside" id=img-list-inout src=list-inout.gif></p>
</div>
<p>In right-to-left text, the markers would have been on the right side of
the box.</p>
</div>
<!-- ====================================================================== -->
<h2 id=list-style-property><span class=secno>5. </span> The ‘<a
href="#list-style"><code class=property>list-style</code></a>’
shorthand property</h2>
<table class=propdef>
<tbody>
<tr>
<th>Name:
<td><dfn id=list-style>list-style</dfn>
<tr>
<th>Value:
<td><‘<a href="#list-style-type"><code
class=property>list-style-type</code></a>’> || <‘<a
href="#list-style-position"><code
class=property>list-style-position</code></a>’> || <‘<a
href="#list-style-image"><code
class=property>list-style-image</code></a>’>
<tr>
<th>Initial:
<td>see individual properties
<tr>
<th>Applies To:
<td>all elements with ‘<code class=css>display:
list-item</code>’
<tr>
<th>Inherited:
<td>yes
<tr>
<th>Percentages:
<td>N/A
<tr>
<th>Media:
<td>visual
<tr>
<th>Computed Value:
<td>see individual properties
</table>
<p>The ‘<a href="#list-style"><code
class=property>list-style</code></a>’ property is a shorthand
notation for setting the three properties ‘<a
href="#list-style-type"><code
class=property>list-style-type</code></a>’, ‘<a
href="#list-style-image"><code
class=property>list-style-image</code></a>’, and ‘<a
href="#list-style-position"><code
class=property>list-style-position</code></a>’ at the same place in
the style sheet.
<div class=example>
<p>For example:</p>
<pre>
UL { list-style: upper-roman inside } /* Any UL */
UL > UL { list-style: circle outside } /* Any UL child of a UL */
</pre>
</div>
<p>Using a value of ‘<a href="#none"><code
class=css>none</code></a>’ in the shorthand is potentially
ambiguous, as ‘<a href="#none"><code
class=css>none</code></a>’ is a valid value for both ‘<a
href="#list-style-image"><code
class=property>list-style-image</code></a>’ and ‘<a
href="#list-style-type"><code
class=property>list-style-type</code></a>’; to resolve this
ambiguity, a value of ‘<a href="#none"><code
class=css>none</code></a>’ in the shorthand must be applied to
whichever of the two properties aren't otherwise set by the shorthand.
<pre class=css-example>
list-style: none disc;
/* Sets the image to ''none'' and the type to ''disc''. */
list-style: none url(bullet.png);
/* Sets the image to ''url(bullet.png)'' and the type to ''none''. */
list-style: none;
/* Sets both image and type to ''none''. */
list-style: none disc url(bullet.png);
/* Syntax error */
</pre>
<p>Although authors may specify ‘<a href="#list-style"><code
class=property>list-style</code></a>’ information directly on list
item elements (e.g., LI in HTML), they should do so with care. The
following rules look similar, but the first declares a descendant selector
and the second a (more specific) child selector.
<pre class=example>
OL.alpha LI { list-style: lower-alpha } /* Any LI descendant of an OL */
OL.alpha > LI { list-style: lower-alpha } /* Any LI child of an OL */
</pre>
<p>Authors who use only the descendant selector may not achieve the results
they expect. Consider the following rules:
<pre class=html-example>
<!doctype html>
<html>
<head>
<title>WARNING: Unexpected results due to cascade</title>
<style>
ol.alpha li { list-style: lower-alpha; }
ul li { list-style: disc; }
</style>
</head>
<body>
<ol class=alpha>
<li>level 1
<ul>
<li>level 2</li>
</ul>
</li>
</ol>
</body>
</html>
</pre>
<p>The desired rendering would have level 1 list items with ‘<a
href="#lower-alpha"><code class=property>lower-alpha</code></a>’
labels and level 2 items with ‘<a href="#disc"><code
class=property>disc</code></a>’ labels. However, the cascading order
will cause the first style rule (which includes specific class
information) to mask the second. The following rules solve the problem by
employing a child selector instead:
<pre class=example>
OL.alpha > LI { list-style: lower-alpha }
UL LI { list-style: disc }
</pre>
<p>Another solution would be to specify ‘<a href="#list-style"><code
class=property>list-style</code></a>’ information only on the list
type elements:
<pre class=example>
OL.alpha { list-style: lower-alpha }
UL { list-style: disc }
</pre>
<p>Inheritance will transfer the ‘<a href="#list-style"><code
class=property>list-style</code></a>’ values from OL and UL elements
to LI elements. This is the recommended way to specify list style
information.</p>
<!-- ====================================================================== -->
<h2 id=marker-pseudoelement><span class=secno>6. </span> Markers: The
‘<code class=css>::marker</code>’ pseudo-element</h2>
<p>Markers are created by setting an element's ‘<code
class=property>display</code>’ property to ‘<code
class=css>list-item</code>’ or ‘<a
href="#inline-list-item"><code
class=css>inline-list-item</code></a>’. The marker box is only
created if the computed value of the ‘<code
class=property>content</code>’ property for the pseudo-element is
not ‘<a href="#none"><code class=css>none</code></a>’.
<p>Just like other generated content, markers generate a box when they're
created, which has margins, border, padding, and everything else a box
normally has. Markers are placed at the beginning of their superior
parent's content, before the ::before pseudo-element (if it exists).
Marker boxes are inline by default, though certain values for ‘<a
href="#list-style-position"><code
class=property>list-style-position</code></a>’ on the list item can
make the marker box positioned, which can have an effect on the computed
value of display.
<div class=html-example>
<p>In the following example, the content is centered within a marker box
of a fixed width. This document:</p>
<pre class=html-example>
<!doctype html>
<html>
<head>
<title>Content alignment in the marker box</title>
<style>
LI::marker {
content: "(" counter(counter) ")";
width: 6em;
text-align: center;
}
LI {
display: list-item;
counter-increment: counter;
}
</style>
</head>
<body>
<ol>
<li>This is the first item.</li>
<li>This is the second item.</li>
<li>This is the third item.</li>
</ol>
</body>
</html>
</pre>
<p>should render something like this:</p>
<pre>
(1) This is the
first item.
(2) This is the
second item.
(3) This is the
third item.
</pre>
</div>
<p>The next example uses markers to number notes (paragraphs).
<div class=html-example>
<p>The following document:</p>
<pre class=html-example>
<!doctype html>
<html>
<head>
<title>Markers to create numbered notes</title>
<style>
P { margin-left: 12 em; }
P.Note::marker {
content: url("note.gif") "Note " counter(note-counter) ":";
text-align: left;
width: 10em;
}
P.Note {
display: list-item;
counter-increment: note-counter;
}
</style>
</head>
<body>
<p>This is the first paragraph in this document.</p>
<p class="Note">This is a very short document.</p>
<p>This is the end.</p>
</body>
</html>
</pre>
<p>should render something like this:</p>
<pre>
This is the first paragraph
in this document.
Note 1: This is a very short
document.
This is the end.
</pre>
</div>
<div class=html-example>
<p>The following example illustrates how markers may be offset from their
element. This HTML application and style sheet:</p>
<pre class=html-example>
<!doctype html>
<html>
<head>
<title>Marker example</title>
<style>
P { margin-left: 8em } /* Make space for counters */
LI::marker { margin: 0 3em 0 0; content: counter(list-item, lower-roman) "."; }
LI { display: list-item }
</style>
</head>
<body>
<p>This is a long preceding paragraph ...</p>
<ol>
<li>This is the first item.</li>
<li>This is the second item.</li>