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[CSS2.1] Margin collapse

From: Staffan Mhln <staffan.mahlen@comhem.se>
Date: Thu, 05 Aug 2004 18:21:57 +0200
To: www-style@w3.org
Message-ID: <41127AC5.6988.24EB1C@localhost>

What is the intention of and examples of the collapse-through definition at 
http://www.w3.org/TR/CSS21/box.html#collapsing-margins:
"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.

    * 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.
    * 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 top border."


I also think that the 8.3.1 section is rather elaborate description of a difficult feature that 
often confuses authors, which should require at least the following examples:

<p>...</p>
<!-- trivial collapse here-->
<p>...</p>

<p>...</p>
<!-- tripple-collapse here-->
<blockquote>
  <p>...</p>
</blockquote>

And possibly an example of the collapse-through feature, depending on what its 
examples are.

 /Staffan
Received on Thursday, 5 August 2004 12:33:25 GMT

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