csswg-drafts/css3-lists/Overview.html at eb3fba5a47c2c6697f461d7fe6ff1fca60367098 · w3c/csswg-drafts · GitHub

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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

<html>
 <head>
  <title>CSS Lists Module Level 3</title>
  <link href="../default.css" rel=stylesheet type="text/css">

  <style type="text/css">
   td, th { padding: 0 0.5em; }
   .numbering td, .numbering th { vertical-align: top; }
   .mapping th { text-align: right; }
   .mapping td { text-align: center; }
   .roman-example { padding: 0.75em; background: white; color: black; margin: 0.25em 0; display: block; }
   .hebrew { display: block; }
   .hebrew-example thead { display: none; }
   .hebrew-example tbody { display: table; float: left; margin: 1em 2em 0.5em; }
   .hebrew-example tr > :first-child { text-align: right; }
   .hebrew-example tr > :last-child { text-align: left; }
   .hebrew-example + * { clear: both; }
  </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 Module Level 3</h1>

   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 4 June 2009</h2>

   <dl>
    <dt>This version:

    <dd><!-- <a href="http://www.w3.org/TR/2009/WD-css3-lists-20090604">http://www.w3.org/TR/2009/WD-css3-lists-20090604</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-background">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>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 &#x00C7;el&#x0131&#x0307;k</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> &copy; 2009 <a
    href="http://www.w3.org/"><acronym title="World Wide Web
    Consortium">W3C</acronym></a><sup>&reg;</sup> (<a
    href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute
    of Technology">MIT</acronym></a>, <a
    href="http://www.ercim.org/"><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&nbsp;3 relating to list styling. It
   includes and extends the functionality of CSS level&nbsp;2 <a
   href="#CSS21" rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>, which builds
   on CSS level&nbsp;1 <a href="#CSS1"
   rel=biblioentry>[CSS1]<!--{{CSS1}}--></a>. The main extensions compared to
   level&nbsp;2 are <span class=issue>summarize here</span>.

  <h2 class="no-num no-toc" id=status>Status of this document</h2>

  <p><strong>This document has been unowned since 7 November 2002.</strong></p>
  <!--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">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 &#8220;css3-lists&#8221; in the subject, preferably like this:
   &#8220;[<!---->css3-lists<!---->] <em>&hellip;summary of
   comment&hellip;</em>&#8221;

  <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="#list-content-the-list-style-type-propert"><span
    class=secno>3 </span>List Content: The <span class=property>&lsquo;<code
    class=property>list-style-type</code>&rsquo;</span> property</a>
    <ul class=toc>
     <li><a href="#glyphs"><span class=secno>3.1 </span>Glyphs</a>

     <li><a href="#algorithmic"><span class=secno>3.2 </span>Algorithmic</a>

     <li><a href="#numeric"><span class=secno>3.3 </span>Numeric</a>

     <li><a href="#alphabetic"><span class=secno>3.4 </span>Alphabetic</a>

     <li><a href="#symbolic"><span class=secno>3.5 </span>Symbolic</a>

     <li><a href="#non-repeating"><span class=secno>3.6
      </span>Non-repeating</a>

     <li><a href="#unsupported-list-styles"><span class=secno>3.7
      </span>Unsupported list styles</a>
    </ul>

   <li><a href="#list-content-the-list-style-image-proper"><span
    class=secno>4 </span>List Content: The <span class=property>&lsquo;<code
    class=property>list-style-image</code>&rsquo;</span> property</a>

   <li><a href="#list-content-generating-the-computed-val"><span
    class=secno>5 &l
DE9
t;/span>List Content: Generating the computed value of the
    <span class=property>&lsquo;<code
    class=property>content</code>&rsquo;</span> property</a>

   <li><a href="#marker-position-the-list-style-position-"><span
    class=secno>6 </span>Marker Position: The <span
    class=property>&lsquo;<code
    class=property>list-style-position</code>&rsquo;</span> property</a>

   <li><a href="#the-list-style-shorthand-property"><span class=secno>7
    </span>The <span class=property>&lsquo;<code
    class=property>list-style</code>&rsquo;</span> shorthand property</a>

   <li><a href="#markers-the-marker-pseudo-element"><span class=secno>8
    </span>Markers: The <span class=css>::marker</span> pseudo-element</a>

   <li><a href="#profiles"><span class=secno>9 </span>Profiles</a>

   <li><a href="#html4"><span class=secno>10 </span>Sample style sheet for
    HTML 4.0</a>

   <li class=no-num><a href="#acknowledgments">Acknowledgments</a>

   <li class=no-num><a href="#changes">Changes From CSS2</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>
&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN"&gt;
&lt;HTML&gt;
 &lt;HEAD&gt;
  &lt;TITLE&gt;Creating a list with markers&lt;/TITLE&gt;
  &lt;STYLE type="text/css"&gt;
   LI::marker { content: "(" counter(list-item, lower-roman) ")"; }
   LI { display: list-item; }
  &lt;/STYLE&gt;
 &lt;/HEAD&gt;
 &lt;BODY&gt;
  &lt;OL&gt;
   &lt;LI&gt; This is the first item. &lt;/LI&gt;
   &lt;LI&gt; This is the second item. &lt;/LI&gt;
   &lt;LI&gt; This is the third item. &lt;/LI&gt;
  &lt;/OL&gt;
 &lt;/BODY&gt;
&lt;/HTML&gt;
</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.

  <h2 id=declaring-a-list-item><span class=secno>2 </span>Declaring a List
   Item</h2>

  <p>To declare a list item, the <span class=property>&lsquo;<code
   class=property>display</code>&rsquo;</span> property should be set to
   &lsquo;<code class=property>list-item</code>&rsquo;. This, in addition to
   generating a <span class=css>::marker</span> pseudo-element and enabling
   the properties described below for that element, causes that element to
   increment the list item counter <span class=css>list-item</span>. (This
   does not affect the specified or computed values of the counter
   properties.)

  <p>The <span class=css>list-item</span> counter is a real counter, and can
   be directly affected using the <span class=property>&lsquo;<code
   class=property>counter-increment</code>&rsquo;</span> and <span
   class=property>&lsquo;<code
   class=property>counter-reset</code>&rsquo;</span> properties. It can also
   be used in the counter() and counters() function forms.

  <p class=issue>The CSS3 box module may define other <span
   class=property>&lsquo;<code class=property>display</code>&rsquo;</span>
   values which generate a list marker. These should also affect the
   &lsquo;<code class=property>list-item</code>&rsquo; counter.

  <p>Note that this new model makes the <span class=css>marker</span> display
   type redundant. That display type is therefore obsolete in the CSS3 Lists
   model.

  <h2 id=list-content-the-list-style-type-propert><span class=secno>3
   </span>List Content: The <span class=property>&lsquo;<code
   class=property><a
   href="#list-style-type">list-style-type</a></code>&rsquo;</span> property</h2>

  <table class=propdef>
   <tbody>
    <tr>
     <td><em>Name:</em>

     <td><dfn id=list-style-type>list-style-type</dfn>

    <tr>
     <td><em>Value:</em>

     <td><a href="#ltglyphgt">&lt;glyph&gt;</a> | <a
      href="#ltalgorithmicgt">&lt;algorithmic&gt;</a> | <a
      href="#ltnumericgt">&lt;numeric&gt;</a> | <a
      href="#ltalphabeticgt">&lt;alphabetic&gt;</a> | <a
      href="#ltsymbolicgt">&lt;symbolic&gt;</a> | <a
      href="#ltnon-repeatinggt">&lt;non-repeating&gt;</a> | normal | none

    <tr>
     <td><em>Initial:</em>

     <td>disc

    <tr>
     <td><em>Applies�to:</em>

     <td>all elements with &lsquo;<code class=css>display:
      list-item</code>&rsquo;

    <tr>
     <td><em>Inherited:</em>

     <td>yes

    <tr>
     <td><em>Percentages:</em>

     <td>N/A

    <tr>
     <td><em>Media:</em>

     <td>visual

    <tr>
     <td><em>Computed value:</em>

     <td>specified value

    <tr>
     <td><em>Depends on:</em>

     <td>none
  </table>

  <p>This property specifies the default appearance of the list item marker
   if <span class=property>&lsquo;<code class=property><a
   href="#list-style-image">list-style-image</a></code>&rsquo;</span> has the
   value &lsquo;<code class=property>none</code>&rsquo; or if the image
   pointed to by the URI cannot be displayed. The value &lsquo;<code
   class=property>none</code>&rsquo; specifies no marker, otherwise there are
   six types of marker: glyphs, algorithmic systems, numeric systems,
   alphabetic systems, symbolic systems, and non-repeating systems.

  <p>Glyphs are single characters, whereas algorithmic, numeric, alphabetic,
   symbolic and non-repeating systems are designed so that each item in that
   style gets a deterministicly different marker. This makes lists easier to
   navigate.

  <p>Most numbering systems have a suffix defined. It is used when generating
   the default content for the marker.

  <dl>
   <dt><dfn id=normal>normal</dfn>

   <dd> Causes the list-style-type of the counter to be used, as declared by
    the appropriate <span class=css>@counter</span> rule. In the context of
    an <span class=css>@counter</span> rule, equivalent to <a
    href="#decimal">decimal</a>.
  </dl>

  <p>Other values are defined in the following sections. User agents should
   follow these algorithms unless a more normative source is found.

  <h3 id=glyphs><span class=secno>3.1 </span>Glyphs</h3>

  <p>All markers with the same glyph style should use the same glyph. To
   obtain other glyphs, authors should use the <span
   class=property>&lsquo;<code class=property>content</code>&rsquo;</span>
   property of the <span class=css>::marker</span> pseudo-element.</p>
  <!-- Their exact rendering depends on the user agent. -->

  <dl>
   <dt><dfn id=ltglyphgt>&lt;glyph&gt;</dfn>

   <dd> box | check | circle | diamond | disc | hyphen | square</dd>
   <!-- these definitions are stupid. circle and square should both have the same fill type, disc and
 box should have the opposite fill type. I hate having to be backwards compatible. -->

   <dt><dfn id=box>box</dfn>

   <dd>A hollow square. (like &#x25A1; U+25A1 WHITE SQUARE, &#x25FB; U+25FB
    WHITE MEDIUM SQUARE, or &#x25FD; U+25FD WHITE MEDIUM SMALL SQUARE)</dd>
   <!-- in MacIE (?) -->

   <dt><dfn id=check>check</dfn>

   <dd>A check mark. On interactive media, it is suggested that the same
    glyph which is used on the platform to render a checked menu item be used
    for &lsquo;<code class=property><a href="#check">check</a></code>&rsquo;.
    (like &#x2713; U+2713 CHECK MARK)</dd>
   <!-- UI module -->

   <dt><dfn id=circle>circle</dfn>

   <dd>A hollow circle. (like &#x25E6; U+25E6 WHITE BULLET)</dd>
   <!-- in Mozilla, WinIE, Opera, HTML4 -->

   <dt><dfn id=diamond>diamond</dfn>

   <dd>A filled diamond. On interactive media, it is suggested that the same
    glyph which is used on the platform next to a selected menu item be used
    for &lsquo;<code class=property><a
    href="#diamond">diamond</a></code>&rsquo;. On some platforms, this is
    similar to &lsquo;<code class=property><a
    href="#disc">disc</a></code>&rsquo;. (like &#x25C6; U+25C6 BLACK DIAMOND
    or &#x2666; U+2666 BLACK DIAMOND SUIT)</dd>
   <!-- UI
 module -->

   <dt><dfn id=disc>disc</dfn>

   <dd>A filled circle. (like &#x2022; U+2022 BULLET)</dd>
   <!-- in Mozilla, WinIE, Opera, HTML4 -->

   <dt><dfn id=hyphen>hyphen</dfn>

   <dd>A hyphen bullet. (like &#x2043; U+2043 HYPHEN BULLET or &#x2013;
    U+2013 EN DASH)

   <dt><dfn id=square>square</dfn>

   <dd>A filled square. (like &#x25A0; U+25A0 BLACK SQUARE, &#x25FC; U+25FC
    BLACK MEDIUM SQUARE, or &#x25FE; U+25FE BLACK MEDIUM SMALL SQUARE)</dd>
   <!-- in Mozilla, WinIE. A hollow square in Opera, HTML4. -->
   <!-- &#x2023; U+2023 TRIANGULAR BULLET
      &#x204C; U+204C BLACK LEFTWARDS BULLET
      &#x204D; U+204D BLACK RIGHTWARDS BULLET -->
  </dl>

  <div class=issue>
   <p>The definitions above may be removed and made UA-dependent if it is
    found that there are discrepancies in the existing implementations.</p>

   <p>We could add more values, there are certainly plenty to choose from in
    UNICODE. How about a star? Or a triangle? Note that the stylesheet of
    this document uses triangular bullets for notes, and yet that can only be
    described using a pseudo-element, content property, and unicode escape.
    Is that too much effort for a simple triangle?</p>

   <p>A future level of CSS may provide a way to specify different bullet
    types at arbitrary nesting levels. The Working Group considered adding an
    <a class=css href="#auto">auto</a> value with the following definition,
    but decided not to include it in this release: "The <dfn
    id=auto>auto</dfn> value is intended to cause the UA to use a list
    numbering style different from that of the nearest ancestor <span
    class=css>list-item</span> element. The exact rendering depends on the
    user agent."</p>
  </div>

  <p>Glyphs have no suffix.

  <h3 id=algorithmic><span class=secno>3.2 </span>Algorithmic</h3>

  <p>Algorithmic systems are the most complicated and are described first.
   For these algorithms, it is assumed that the rendering engine will apply
   the bidirectionality algorithm <em>after</em> generating the numeric
   strings.

  <p class=note>Note: Readers not accustomed to reading bidirectional text
   should pay close attention to the directionality of characters versus
   their associated UNICODE codepoints. All codepoints are given in logical
   order, but example strings in this document should be rendered in correct
   reading order.

  <dl>
   <dt><dfn id=ltalgorithmicgt>&lt;algorithmic&gt;</dfn>

   <dd> armenian | cjk-ideographic | ethiopic-numeric | georgian | hebrew |
    japanese-formal | japanese-informal | <!--  korean -->
    <!--  korean-check | --> <!--  korean-hangul | --> lower-armenian |
    lower-roman | simp-chinese-formal | simp-chinese-informal | syriac |
    tamil | trad-chinese-formal | trad-chinese-informal | upper-armenian |
    upper-roman

   <dt><dfn id=lower-armenian>lower-armenian</dfn>

   <dd>This is a simple additive system defined for the range 1 to 9999.
    <!-- The digits are split into two groups of four (if there are
less than eight digits, the least significant group is filled first).
Within each group, -->
    The appropriate digits are picked from the following list (at most one
    per column) and written in descending order by value (thousands first).
    <!-- Any characters in the most significant group are
then combined with a macron accent, &#x25CC;&#x304; U+0304.
25CC is a dotted circle -->

    <table>
     <caption>Lower-armenian numbering system</caption>

     <thead>
      <tr>
       <th colspan=3>Thousands

       <th colspan=3>Hundreds

       <th colspan=3>Tens

       <th colspan=3>Units

      <tr>
       <th>Values

       <th colspan=2>Codepoints

       <th>Values

       <th colspan=2>Codepoints

       <th>Values

       <th colspan=2>Codepoints

       <th>Values

       <th colspan=2>Codepoints

     <tbody>
      <tr>
       <td>1000

       <td>&#x057C;

       <td>U+057C

       <td>100

       <td>&#x0573;

       <td>U+0573

       <td>10

       <td>&#x056A;

       <td>U+056A

       <td>1

       <td>&#x0561;

       <td>U+0561

      <tr>
       <td>2000

       <td>&#x057D;

       <td>U+057D

       <td>200

       <td>&#x0574;

       <td>U+0574

       <td>20

       <td>&#x056B;

       <td>U+056B

       <td>2

       <td>&#x0562;

       <td>U+0562

      <tr>
       <td>3000

       <td>&#x057E;

       <td>U+057E

       <td>300

       <td>&#x0575;

       <td>U+0575

       <td>30

       <td>&#x056C;

       <td>U+056C

       <td>3

       <td>&#x0563;

       <td>U+0563

      <tr>
       <td>4000

       <td>&#x057F;

       <td>U+057F

       <td>400

       <td>&#x0576;

       <td>U+0576

       <td>40

       <td>&#x056D;

       <td>U+056D

       <td>4

       <td>&#x0564;

       <td>U+0564

      <tr>
       <td>5000

       <td>&#x0580;

       <td>U+0580

       <td>500

       <td>&#x0577;

       <td>U+0577

       <td>50

       <td>&#x056E;

       <td>U+056E

       <td>5

       <td>&#x0565;

       <td>U+0565

      <tr>
       <td>6000

       <td>&#x0581;

       <td>U+0581

       <td>600

       <td>&#x0578;

       <td>U+0578

       <td>60

       <td>&#x056F;

       <td>U+056F

       <td>6

       <td>&#x0566;

       <td>U+0566

      <tr>
       <td>7000

       <td>&#x0582;

       <td>U+0582

       <td>700

       <td>&#x0579;

       <td>U+0579

       <td>70

       <td>&#x0570;


       <td>7

       <td>&#x0567;

       <td>U+0567

      <tr>
       <td>8000

       <td>&#x0583;

       <td>U+0583

       <td>800

       <td>&#x057A;

       <td>U+057A

       <td>80

       <td>&#x0571;

       <td>U+0571

       <td>8

       <td>&#x0568;

       <td>U+0568

      <tr>
       <td>9000

       <td>&#x0584;

       <td>U+0584

       <td>900

       <td>&#x057B;

       <td>U+057B

       <td>90

       <td>&#x0572;

       <td>U+0572

       <td>9

       <td>&#x0569;

       <td>U+0569
    </table>
    <!--
 <p class="issue">There are two letters for 10,000 and 20,000 (U+0555
 and U+0556 respectively), but whether and how they should be used is
 unclear.</p>
 Some clarification: http://lists.w3.org/Archives/Public/www-style/2009Feb/0348.html
-->

    <p>The suffix for the armenian numbering system is a dot (&#x002E; U+002E
     FULL STOP).</p>

    <p>Numbers outside the range of the armenian system are rendered using
     the decimal numbering style.</p>

    <div class=example>
     <p>Decimal 2951 in lower-armenian is &#x057D;&#x057B;&#x056E;&#x0561;
      U+057D U+057B U+056E U+0561.</p>
    </div>

   <dt><dfn id=cjk-ideographic>cjk-ideographic</dfn>

   <dd>The cjk-ideographic algorithm is used by several numbering systems,
    using different sets of digits. These systems are defined for numbers
    greater than or equal to 0 and less than 10<sup>16</sup>. Numbers less
    than zero or equal to or greater than 10<sup>16</sup> should use the
    decimal system. The core algorithm is as follows:
    <ol>
     <li>Split the decimal number into groups of four digits, starting with
      the least significant digit.

     <li>Ignoring groups that have the value zero, append the second group
      marker to the second group, the third group marker to the third group,
      and the fourth group marker to the fourth group. These markers are
      defined in the tables for the specific numbering systems. The first
      group has no marker.

     <li>For each group, ignoring digits that have the value zero, append the
      second digit marker to the second digit, the third digit marker to the
      third digit, and the fourth digit marker to the fourth digit. These
      markers are defined in the tables for the specific numbering systems.
      The first digit has no marker.

     <li>For any group with a value less than 20, remove the second digit
      (the 1 in the tens column). Leave any associated markers.

     <li>Concatenate the groups back into a single string, least significant
      group last.

     <li>Collapse any consecutive runs of 0 digits to a single 0.

     <li>Replace each digit with the relevant character selected from the
      numbering system's table.
    </ol>

    <p>The suffix for the cjk-ideographic numbering systems is a dot
     (&#x002E; U+002E FULL STOP). <span class=issue>Is there a better suffix
     to use?</span></p>

    <p>If specified explicitly, the cjk-ideograph keyword should be handled
     like trad-chinese-informal.</p>

   <dt><dfn id=ethiopic-numeric>ethiopic-numeric</dfn>

   <dd>The following algorithm converts decimal digits to ethiopic numbers.
    <ol>
     <li>Split the number into groups of two digits, starting with the least
      significant decimal digit.

     <li>Number each group sequentially, starting from the least significant
      as group number zero.

     <li>If the group has an odd number (as given in the previous step) and
      has the value 1, or if the group is the most significant one and has
      the value 1, or if the group has the value zero, then remove the digit
      (but leave the group, so it still has a separator appended below).

     <li>For each remaining digit, substitute the relevant ethiopic character
      from the list below.
      <table>
       <caption>Ethiopic numbering system</caption>

       <thead>
        <tr>
         <th colspan=3>Tens

         <th colspan=3>Units

        <tr>
         <th>Values

         <th colspan=2>Codepoints

         <th>Values

         <th colspan=2>Codepoints

       <tbody>
        <tr>
         <td>10

         <td>&#x1372;

         <td>U+1372

         <td>1

         <td>&#x1369;

         <td>U+1369

        <tr>
         <td>20

         <td>&#x1373;

         <td>U+1373

         <td>2

         <td>&#x136A;

         <td>U+136A

        <tr>
         <td>30

         <td>&#x1374;

         <td>U+1374

         <td>3

         <td>&#x136B;

         <td>U+136B

        <tr>
         <td>40

         <td>&#x1375;

         <td>U+1375

         <td>4

         <td>&#x136C;

         <td>U+136C

        <tr>
         <td>50

         <td>&#x1376;

         <td>U+1376

         <td>5

         <td>&#x136D;

         <td>U+136D

        <tr>
         <td>60

         <td>&#x1377;

         <td>U+1377

         <td>6

         <td>&#x136E;

         <td>U+136E

        <tr>
         <td>70

         <td>&#x1378;

         <td>U+1378

         <td>7

         <td>&#x136F;

         <td>U+136F

        <tr>
         <td>80

         <td>&#x1379;

         <td>U+1379

         <td>8

         <td>&#x1370;

         <td>U+1370

        <tr>
         <td>90

         <td>&#x137A;

         <td>U+137A

         <td>9

         <td>&#x1371;

         <td>U+1371
      </table>

     <li>For each group with an odd number (as given in the second step),
      append &#x137B U+137B.

     <li>For each group with an even number (as given in the second step),
      except the group with number 0, append &#x137C U+137C.

     <li>Concatenate the groups into one string.

    <p>This system is defined for all numbers greater than zero. For zero and
     negative numbers, the decimal system is used instead.</p>

    <p>The suffix for the ethiopic-numeric numbering systems is a dot
     (&#x002E; U+002E FULL STOP). <span class=issue>Is there a better suffix
     to use? <strong>The alphabetic ethiopic systems use a different
     suffix.</strong></span></p>