[css2] Generated. Do not edit!

--HG--
extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%403095

Author: bert-github

css2/box.html

@@ -358,117 +358,138 @@ <H2>8.3 <a name="margin-properties">Margin properties</a>:
 
 <H3>8.3.1 <a name="collapsing-margins">Collapsing margins</a></H3>
 
-<P>In this specification, the expression <a name="x26"><span class="index-def"
-title="collapsing margin"><dfn>collapsing margins</dfn></span></a> means
-that adjoining margins (no non-empty content, padding or border areas
-or <a href="visuren.html#clearance">clearance</a> separate them) of
-two or more boxes (which may be next to one another or nested) combine
-to form a single margin.
+<P>In CSS, the adjoining margins of two or more boxes (which might or
+might not be siblings) can combine to form a single margin. Margins
+that combine this way are said to <dfn>collapse</dfn>, and the
+resulting combined margin is called a <a name="x26"><span class="index-def"
+title="collapsing margin"><dfn>collapsed margin</dfn></span></a>.
+
+<P>Adjoining vertical margins collapse, except:
+
+<UL>
+  <LI>Margins of the root element's box do not collapse.
+
+  <LI>If the top and bottom margins of an element with <a
+  href="visuren.html#clearance">clearance</a> are adjoining, its
+  margins collapse with the adjoining margins of following siblings
+  but that resulting margin does not collapse with the bottom margin
+  of the parent block.
+</UL>
+
+<P>Horizontal margins never collapse.
+
+<P ID="what-is-adjoining">Two margins are <a name="x27"><span class="index-def"
+title="adjoining margins"><DFN>adjoining</DFN></span></a> if and only if:
+
+<UL>
+  <LI>both belong to in-flow <a
+  href="visuren.html#block-boxes">block-level boxes</a> that
+  participate in the same <a
+  href="visuren.html#block-formatting">block formatting context</a>
+
+  <LI>no line boxes, no clearance, no padding and no border separate
+  them
+
+  <LI>both belong to vertically-adjacent box edges, i.e. form one of
+  the following pairs:
+
+  <UL>
+    <LI>top margin of a box and top margin of its first in-flow child
+
+    <LI>bottom margin of box and top margin of its next in-flow
+    following sibling
+
+    <LI>bottom margin of a last in-flow child and bottom margin of its
+    parent if the parent has 'auto' computed height
+
+    <LI>top and bottom margins of a box that does not establish a new
+    block formatting context and that has zero computed <a href="visudet.html#propdef-min-height" class="noxref"><span
+    class="propinst-min-height">'min-height'</span></a>, zero or 'auto'
+    computed <a href="visudet.html#propdef-min-height" class="noxref"><span class="propinst-min-height">'height'</span></a>, and no
+    in-flow children
+  </UL>
+</UL>
+
+<P>A collapsed margin is considered adjoining to another margin if any
+of its component margins is adjoining to that margin.
+
+<P CLASS=note><STRONG>Note.</STRONG> Adjoining margins can be
+generated by elements that are not related as siblings or ancestors.
+
+<DIV CLASS=note>
+<P><STRONG>Note</STRONG> the above rules imply that:
+
+<UL>
+  <LI>Margins between a <a href="visuren.html#floats">floated</a> box
+  and any other box do not collapse (not even between a float and its
+  in-flow children).
+
+  <LI>Margins of elements that establish new block formatting contexts
+  (such as floats and elements with <a href="visufx.html#propdef-overflow" class="noxref"><span
+  class="propinst-overflow">'overflow'</span></a> other than 'visible') do
+  not collapse with their in-flow children.
+
+  <LI>Margins of <a
+  href="visuren.html#absolutely-positioned">absolutely positioned</a>
+  boxes do not collapse (not even with their in-flow children).
+
+  <LI>Margins of inline-block boxes do not collapse (not even with
+  their in-flow children).
+
+  <LI>The bottom margin of an in-flow block-level element always
+  collapses with the top margin of its next in-flow block-level
+  sibling, unless that sibling has clearance.
+
+  <LI>The top margin of an in-flow block element collapses with its
+  first in-flow block-level child's top margin if the element has no
+  top border, no top padding, and the child has no clearance.
+
+  <LI>The bottom margin of an in-flow block box with a <a href="visudet.html#propdef-height" class="noxref"><span
+  class="propinst-height">'height'</span></a> of 'auto' and a <a href="visudet.html#propdef-min-height" class="noxref"><span
+  class="propinst-min-height">'min-height'</span></a> of zero collapses
+  with its last in-flow block-level child's bottom margin if the box
+  has no bottom padding and no bottom border and the child's bottom
+  margin does not collapse with a top margin that has clearance.
+
+  <LI>A box's own margins collapse if the <a href="visudet.html#propdef-min-height" class="noxref"><span
+  class="propinst-min-height">'min-height'</span></a> property is zero,
+  and it has neither top or bottom borders nor top or bottom padding,
+  and it has a <a href="visudet.html#propdef-height" class="noxref"><span class="propinst-height">'height'</span></a> of either
+  0 or 'auto', and it does not contain a line box, and all of its
+  in-flow children's margins (if any) collapse.
+</UL>
+</DIV>
+
+<P>When two or more margins collapse, the resulting margin width is
+the maximum of the collapsing margins' widths. In the case of negative
+margins, the maximum of the absolute values of the negative adjoining
+margins is deducted from the maximum of the positive adjoining
+margins.  If there are no positive margins, the maximum of the
+absolute values of the adjoining margins adjoining margins is deducted
+from zero.
+
+<P ID="collapsed-through">If the top and bottom margins of a box are
+adjoining, then it is possible for margins to <a name="x28"><span
+class="index-def"><DFN>collapse through</DFN></span></a> it. In this case,
+the position of the element depends on its relationship with the other
+elements whose margins are being collapsed.
 
-<P>In CSS&nbsp;2.1, <a name="x27"><span class="index-inst" title="horizontal
-margin|margin::horizontal">horizontal margins</span></a> never collapse.
+<UL>
+  <LI>If the element's margins are collapsed with its parent's top
+  margin, the top border edge of the box is defined to be the same as
+  the parent's.
 
-<P><a name="x29"><span class="index-inst" title="vertical margin|margin::vertical">
-Vertical margins</span></a> may collapse between certain boxes:</p>
+  <LI>Otherwise, either the element's parent is not taking part in the
+  margin collapsing, or only the parent's bottom margin is
+  involved. The position of the element's top border edge is the same
+  as it would have been if the element had a non-zero bottom border.
+</UL>
 
-<ul>
-<li>Two or more adjoining vertical margins of <a
-href="visuren.html#block-boxes">block-level</a> boxes in the <a
-href="visuren.html#normal-flow">normal flow</a> collapse. The
-resulting margin width is the maximum of the adjoining margin widths.
-In the case of negative margins, the maximum of the absolute values
-of the negative
-adjoining margins is deducted from the maximum of the positive
-adjoining margins. If there are no positive margins, the absolute
-maximum of the negative adjoining margins is deducted from zero.
-<strong>Note.</strong> Adjoining boxes may be generated by
-elements that are not related as siblings or ancestors.
-
-<li>Vertical margins between a <a
-href="visuren.html#floats">floated</a> box and any other box do not
-collapse (not even between a float and its in-flow children).
-
-<li>Vertical margins of elements that establish new block formatting
-contexts (such as floats and elements with <a href="visufx.html#propdef-overflow" class="noxref"><span
-class="propinst-overflow">'overflow'</span></a> other than 'visible') do
-not collapse with their in-flow children.
-
-<li>Margins of <a
-href="visuren.html#absolutely-positioned">absolutely</a>
-positioned boxes do not collapse (not even with their
-in-flow children).
-
-<li>Margins of <a name="x31"><span class="index-inst">inline-block</span></a> elements
-do not collapse (not even with their in-flow children).
-
-<li id="collapsed-through">
-If the top and bottom margins of a box are adjoining, then it is
-possible for margins to collapse through it. In this case, the
-position of the element depends on its relationship with the other
-elements whose margins are being collapsed.
-<ul><li>If the element's margins are collapsed with its parent's top
-margin, the top border edge of the box is defined to be the same as
-the parent's.</li>
-<li>Otherwise, either the element's parent is not taking part in the
-margin collapsing, or only the parent's bottom margin is involved. The
-position of the element's top border edge is the same as it would have
-been if the element had a non-zero bottom border.</li></ul>
-
-<p>An element that has <a
-href="visuren.html#clearance">clearance</a> never
-collapses its top margin with its parent block's bottom margin.</p>
-
-<p>Note that the positions of elements that have been collapsed
+<P>Note that the positions of elements that have been collapsed
 through have no effect on the positions of the other elements with
 whose margins they are being collapsed; the top border edge position
-is only required for laying out descendants of these
-elements.</p>
-</li>
-
-<li>Margins of the root element's box do not collapse.</li>
-
-</ul>
-
-<div id="what-is-adjoining">
-
-<p>The bottom margin of an in-flow block-level element is always
-adjoining to the top margin of its next in-flow block-level
-sibling, unless that sibling has <a
-href="visuren.html#clearance">clearance.</a></p>
-
-<p>The top margin of an in-flow block box is adjoining to
-its first in-flow block-level child's top margin if the element has no
-top border, no top padding, and the child has no <a
-href="visuren.html#clearance">clearance.</a></p>
-
-<p>The bottom margin of an in-flow block box with a 'height'
-of 'auto' is adjoining to its last in-flow block-level child's bottom
-margin if the element has no bottom padding or border.
-
-<p>An element's own margins are adjoining if the <a href="visudet.html#propdef-min-height" class="noxref"><span
-class="propinst-min-height">'min-height'</span></a> property is zero, and
-it has neither top or bottom borders nor top or bottom padding, and it has a
-<a href="visudet.html#propdef-height" class="noxref"><span class="propinst-height">'height'</span></a> of either 0 or 'auto',
-and it does not contain a line box, and all of its in-flow children's
-margins (if any) are adjoining.</p>
-
-<p>When an element's own margins collapse, and that element has
-clearance, its top margin collapses with the adjoining
-margins of subsequent siblings but that resulting margin does not
-collapse with the bottom margin of the parent block.</p>
-
-<p>Collapsing is based on the <em>used value</em> of <a href="box.html#propdef-padding" class="noxref"><span
-class="propinst-padding">'padding'</span></a>, <a href="box.html#propdef-margin" class="noxref"><span
-class="propinst-margin">'margin'</span></a>, and <a href="box.html#propdef-border" class="noxref"><span
-class="propinst-border">'border'</span></a> (i.e., after resolving any
-percentages). The collapsed margin is
-calculated over the used value of the various margins.</p>
-
-</div>
+is only required for laying out descendants of these elements.
 
-<P>Please
-consult the <a href="#mpb-examples">examples of margin, padding, and
-borders</a> for an illustration of collapsed margins.
 
 <H2>8.4 <a name="padding-properties">Padding properties</a>:
 <a href="box.html#propdef-padding-top" class="noxref"><span class="propinst-padding-top">'padding-top'</span></a>,
@@ -752,7 +773,7 @@ <H3>8.5.2 <A name="border-color-properties">Border color</A>:
 meanings:</p>
 
 <dl>
-<dt><span class="index-inst" title="&lt;color&gt;"><a name="x49" href="syndata.html#value-def-color" class="noxref"><span
+<dt><span class="index-inst" title="&lt;color&gt;"><a name="x46" href="syndata.html#value-def-color" class="noxref"><span
 class="value-inst-color"><strong>&lt;color&gt;</strong></span></a></span>
 <dd>Specifies a color value.
 <dt><strong>transparent</strong>

css2/changes.html

@@ -533,6 +533,10 @@ <H1><a name="q0">Appendix C. Changes</a></H1>
       <li class="tocline3"><a href="changes.html#q492" class="tocxref">C.7.103  Section&nbsp;E.2 Painting order</a>
       <li class="tocline3"><a href="changes.html#q493" class="tocxref">C.7.104  Appendix&nbsp;G Grammar of CSS&nbsp;2.1</a>
     </ul>
+    <li class="tocline2"><a href="changes.html#q494" class="tocxref">C.8 Changes since the working draft of 7 December 2010</a>
+    <ul class="toc">
+      <li class="tocline3"><a href="changes.html#q495" class="tocxref">C.8.1 8.3.1 Collapsing margins</a>
+    </ul>
   </ul>
 </div>
 <P><em>This appendix is informative, not normative.</em></P>
@@ -6942,6 +6946,21 @@ <h3 id="t.G"><a name="q493">C.7.104 </a><a
 
 
 
+
+
+<h2 id=errata4><a name="q494">C.8 Changes since the working draft of 7 December 2010</a></h2>
+
+
+
+
+<h3 id=u.8.3.1><a name="q495">C.8.1 </a><a
+href="/TR/2010/WD-CSS2-20101207/box.html#collapsing-margins">8.3.1
+Collapsing margins</a></h3>
+
+<p>The section is completely rewritten to make the normative text
+shorter and clearer.
+
+
 <hr class="navbar">
 
 <div class="navbar">

css2/cover.html

@@ -1263,6 +1263,10 @@ <h2><a name="toc">Full Table of Contents</a></h2>
       <li class="tocline3"><a href="changes.html#q492" class="tocxref">C.7.103  Section&nbsp;E.2 Painting order</a>
       <li class="tocline3"><a href="changes.html#q493" class="tocxref">C.7.104  Appendix&nbsp;G Grammar of CSS&nbsp;2.1</a>
     </ul>
+    <li class="tocline2"><a href="changes.html#q494" class="tocxref">C.8 Changes since the working draft of 7 December 2010</a>
+    <ul class="toc">
+      <li class="tocline3"><a href="changes.html#q495" class="tocxref">C.8.1 8.3.1 Collapsing margins</a>
+    </ul>
   </ul>
   <li class="tocline1"><a href="sample.html" class="tocxref">Appendix D. Default style sheet for HTML 4</a>
   <li class="tocline1"><a href="zindex.html" class="tocxref">Appendix E. Elaborate description of Stacking Contexts</a>