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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<title>Visual formatting model</title>
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<hr class="navbar">
<h1><a name="q0">9 Visual formatting model</a></h1>
<div class="subtoc">
<p><strong>Contents</strong>
<ul class="toc">
<li class="tocline2"><a href="visuren.html#visual-model-intro" class="tocxref">9.1 Introduction to the visual formatting model</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#viewport" class="tocxref">9.1.1 The viewport</a>
<li class="tocline3"><a href="visuren.html#containing-block" class="tocxref">9.1.2 <span class="index-def" title="containing block"> Containing blocks</span></a>
</ul>
<li class="tocline2"><a href="visuren.html#box-gen" class="tocxref">9.2 Controlling box generation</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#block-boxes" class="tocxref">9.2.1 Block-level elements and block boxes</a>
<ul class="toc">
<li class="tocline4"><a href="visuren.html#anonymous-block-level" class="tocxref"><ins>9.2.1.1</ins> Anonymous block boxes</a>
</ul>
<li class="tocline3"><a href="visuren.html#inline-boxes" class="tocxref">9.2.2 Inline-level elements and inline boxes</a>
<ul class="toc">
<li class="tocline4"><a href="visuren.html#anonymous" class="tocxref"><ins>9.2.2.1</ins> Anonymous inline boxes</a>
</ul>
<li class="tocline3"><a href="visuren.html#run-in" class="tocxref">9.2.3 <del>Compact boxes 9.2.4</del>Run-in boxes</a>
<li class="tocline3"><a href="visuren.html#display-prop" class="tocxref"> <del>9.2.5</del><ins>9.2.4</ins> The <span class="propinst-display">'display'</span> proper
1898
ty</a>
</ul>
<li class="tocline2"><a href="visuren.html#positioning-scheme" class="tocxref">9.3 Positioning schemes</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#choose-position" class="tocxref">9.3.1 Choosing a positioning scheme: <span class="propinst-position">'position'</span> property</a>
<li class="tocline3"><a href="visuren.html#position-props" class="tocxref">9.3.2 Box offsets: <span class="propinst-top">'top'</span>, <span class="propinst-right">'right'</span>, <span class="propinst-bottom">'bottom'</span>, <span class="propinst-left">'left'</span></a>
</ul>
<li class="tocline2"><a href="visuren.html#normal-flow" class="tocxref">9.4 Normal flow</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#block-formatting" class="tocxref">9.4.1 Block formatting <del>context</del><ins>contexts</ins></a>
<li class="tocline3"><a href="visuren.html#inline-formatting" class="tocxref">9.4.2 Inline formatting <del>context</del><ins>contexts</ins></a>
<li class="tocline3"><a href="visuren.html#relative-positioning" class="tocxref">9.4.3 Relative positioning</a>
</ul>
<li class="tocline2"><a href="visuren.html#floats" class="tocxref">9.5 Floats</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#float-position" class="tocxref">9.5.1 Positioning the float: the <span class="propinst-float">'float'</span> property</a>
<li class="tocline3"><a href="visuren.html#flow-control" class="tocxref">9.5.2 Controlling flow next to floats: the <span class="propinst-clear">'clear'</span> property</a>
</ul>
<li class="tocline2"><a href="visuren.html#absolute-positioning" class="tocxref">9.6 Absolute positioning</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#fixed-positioning" class="tocxref">9.6.1 Fixed positioning</a>
</ul>
<li class="tocline2"><a href="visuren.html#dis-pos-flo" class="tocxref">9.7 Relationships between 'display', 'position', and 'float'</a>
<li class="tocline2"><a href="visuren.html#comparison" class="tocxref">9.8 Comparison of normal flow, floats, and absolute positioning</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#comp-normal-flow" class="tocxref">9.8.1 Normal flow</a>
<li class="tocline3"><a href="visuren.html#comp-relpos" class="tocxref">9.8.2 Relative positioning</a>
<li class="tocline3"><a href="visuren.html#comp-float" class="tocxref">9.8.3 Floating a box</a>
<li class="tocline3"><a href="visuren.html#comp-abspos" class="tocxref">9.8.4 Absolute positioning</a>
</ul>
<li class="tocline2"><a href="visuren.html#layers" class="tocxref">9.9 Layered presentation</a>
<ul class="toc">
<li class="tocline3"><a href="visuren.html#z-index" class="tocxref">9.9.1 Specifying the stack level: the <span class="propinst-z-index">'z-index'</span> property</a>
</ul>
<li class="tocline2"><a href="visuren.html#direction" class="tocxref">9.10 Text direction: the <span class="propinst-direction">'direction'</span> and <span class="propinst-unicode-bidi">'unicode-bidi'</span> properties</a>
</ul>
</div>
<h2>9.1 <a name="visual-model-intro">Introduction to the visual formatting model</a></h2>
<p>This chapter and the next describe the <a name="x0"><span class="index-def"
title="visual formatting model">visual formatting model</span></a>: how user
agents process the <a href="conform.html#doctree">document tree</a>
for visual <a href="media.html">media</a>.
</p>
<p>In the visual formatting model, each element in the document tree
generates zero or more boxes according to the <a href="box.html">box
model</a>. The layout of these boxes is governed by:</p>
<ul>
<li><a href="box.html#box-dimensions">box dimensions</a> and <a
href="#box-gen">type</a>.
</li><li><a href="#positioning-scheme">positioning scheme</a>
(normal flow, float, and <del>absolute).</del><ins>absolute positioning).</ins>
</li><li>relationships between elements
in the <a href="conform.html#doctree">document tree.</a>
</li><li>external information (e.g., viewport size, <a
href="conform.html#intrinsic">intrinsic</a> dimensions of images, etc.).
</li></ul>
<p>The properties defined in this chapter and the next apply to both
<a href="media.html#continuous-media-group">continuous media</a> and
<a href="media.html#paged-media-group">paged media</a>. <span class="paged">
However, the
meanings of the <a href="box.html#margin-properties">margin
properties</a> vary when applied to paged media (see the <a
href="page.html#page-margins">page model</a> for details).
</span>
</p>
<p>The visual formatting model does not specify all aspects of
formatting (e.g., it does not specify a letter-spacing algorithm). <a
href="conform.html#conformance">Conforming user agents</a> may behave
differently for those formatting issues not covered by this
specification.
</p>
<h3>9.1.1 <a name="viewport">The viewport</a></h3>
<p>User agents for <a
href="media.html#continuous-media-group">continuous media</a>
generally offer users a <a name="x1"><span class="index-def" title="viewport">
<dfn>viewport</dfn></span></a> (a window or other
viewing area on the screen) through which users consult a
document. User agents may change the document's layout when the
viewport is resized (see the <a
href="visudet.html#containing-block-details">initial containing block</a>).
</p>
<p>
When the viewport is smaller than the <del>document's initial containing block,</del><ins>area of the canvas on which
the document is rendered,</ins> the user agent should offer a scrolling
mechanism.
There is at most
one viewport per <a href="intro.html#canvas">canvas</a>, but user
agents may render to more than one canvas (i.e., provide different
views of the same document).
</p>
<h3>9.1.2 <span class="index-def" title="containing block">
<a name="containing-block">Containing blocks</a></span>
</h3>
<p>In <del>CSS2,</del><ins>CSS 2.1,</ins> many box positions and sizes are calculated with respect
to the edges
of a rectangular box called a <a name="x3"><span class="index-def"
title="containing block"><dfn>containing block</dfn></span></a>. In
general, generated boxes act as containing blocks for descendant
boxes; we say that a box "establishes" t
A3CA
he containing block for its
descendants. The phrase "a box's containing block" means "the
containing block in which the box lives," not the one it generates.
</p>
<p>Each box is given a position with respect to its containing block,
but it is not confined by this containing block; it may <a
href="visufx.html#overflow">overflow</a>.
</p>
<p>The <a href="visudet.html#containing-block-details"> <del>root of the document tree generates a box that serves as the initial containing block for subsequent layout. The width of the initial containing block may be specified with the 'width' property for the root element. If this property has the value 'auto', the user agent supplies the initial width (e.g., the user agent uses the current width of the viewport ). The height of the initial containing block may be specified with the 'height' property for the root element. If this property has the value 'auto', the containing block height will grow to accommodate the document's content. The initial containing block cannot be positioned or floated (i.e., user agents ignore the 'position' and 'float' properties for the root element). The</del>details</a> of
how a containing block's dimensions are calculated are described in
the <a href="visudet.html">next chapter</a>.
</p>
<h2>9.2 <a name="box-gen">Controlling box generation</a></h2>
<p>The following sections describe the types of boxes that may be
generated in <del>CSS2.</del><ins>CSS 2.1.</ins> A box's type affects, in part, its behavior in the
visual formatting model. The <a href="visuren.html#propdef-display" class="noxref"><span
class="propinst-display">'display'</span></a> property, described below,
specifies a box's type.
</p>
<h3>9.2.1 <a name="block-boxes">Block-level elements and block boxes</a></h3>
<p><span class="index-def" title="block-level
element"><a name="block-level"><dfn>Block-level elements</dfn></a></span> are those elements of the source document that are formatted visually as
blocks (e.g., paragraphs). <del>Several</del><ins>The following</ins> values of the <a href="visuren.html#propdef-display" class="noxref"><span
class="propinst-display">'display'</span></a> property make an element
block-level: 'block', 'list-item', <del>'compact' and 'run-in' (part of the time; see compact and run-in boxes ),</del>and 'table'.
</p>
<p><a name="x5"><span class="index-def" title="block-level box"><dfn>Block-level
<del>elements generate</del><ins>boxes</ins></dfn></span></a> <ins>are boxes that participate in</ins>
a <a href="#block-formatting"> <del>principal</del>block <ins>formatting context.</ins></a> <ins>Each
block-level element generates a</ins> <span class="index-def"
title="principal block-level
box"><a name="principal-box"><dfn><ins>principal block-level</ins>
box</dfn></a></span> that <del>only</del>contains <del>block boxes . The principal block box establishes the containing block for</del>descendant boxes and generated
content and is also the box involved in any positioning scheme.
<del>Principal block boxes participate in a block formatting context .</del>Some block-level elements <ins>may</ins> generate additional boxes <del>outside of</del><ins>in addition
to</ins> the
principal box: 'list-item' <del>elements and those with markers .</del><ins>elements.</ins> These additional boxes are
placed with respect to the principal box.
<p> <del>Anonymous block boxes</del><ins>Except for table boxes, which are described</ins> in a <del>document like this: <DIV> Some text <P>More text </DIV> (and assuming the DIV and the P both have 'display: block'), the DIV appears to have both inline content</del><ins>later chapter, and
replaced elements, a block-level box is also a block container box.
A</ins> <span class="index-def" title="block container box"><a
name="block-container-box"><dfn ><ins>block
container box</ins></dfn></a></span> <ins>either
contains only block-level boxes or establishes an inline formatting
context and thus contains only inline-level boxes. Not all block
container boxes are block-level boxes: non-replaced inline blocks
and non-replaced table cells are block containers but not block-level
boxes. Block-level boxes that are also block containers are
called</ins> <a name="x8"><span class="index-def" title="block box"><dfn><ins>block
boxes</ins></dfn></span></a><ins>.</ins>
<p><ins>The three terms "block-level box," "block container box," and
"block box" are sometimes abbreviated as "block" where unambiguous.</ins>
<h4><ins>9.2.1.1</ins> <a name="anonymous-block-level"><ins>Anonymous block boxes</ins></a></h4>
<p><ins>In a document like this:</ins>
</p>
<pre><code class="html">
<ins><DIV>
Some text
<P>More text
</DIV></ins>
</code></pre>
<p>
<ins>(and assuming the DIV and the P both have 'display: block'), the
DIV appears to have both inline content</ins> and block content. To make it
easier to define the formatting, we assume that there is an <em><a name="x9"><span
class="index-def" title="anonymous">anonymous block box</span></a></em>
around "Some text".
</p>
<div class="figure">
<p><img src="images/anon-block.png" alt="diagram showing the three
boxes for the example above"><SPAN class="dlink"> <A name="img-anon-block" href="images/longdesc/anon-block-desc.html" title="Long description for anonymous block box">[D]</A></SPAN>
</p><p class="caption">Diagram showing the
three boxes, of which one is anonymous, for the example above.
</p></div>
<p>In other words: if a block <ins>container</ins> box (such as that generated
for the DIV above) has <del>another block</del><ins>a block-level</ins> box inside it (such as the P
above), then we force it to have <em>only</em> <del>block</del><ins>block-level</ins> boxes
inside <del>it, by wrapping</del><ins>it.</ins>
<p><ins>When an inline box contains an in-flow block-level box, the inline box
(and its inline ancestors within the same line box) are broken around
the block-level box (and</ins> any <ins>block-level siblings that are consecutive
or separated only by collapsible whitespace and/or out-of-flow
elements), splitting the</ins> inline <ins>box into two boxes (even if either
side is empty), one on each side of the block-level box(es). The line</ins>
boxes <ins>before the break and after the
break are enclosed</ins> in <del>an</del>anonymous block <ins>boxes, and the block-level box
becomes a sibling of those anonymous boxes. When such an inline box is
affected by relative positioning, any resulting translation also
affects the block-level box contained in the inline</ins> box.
<div class="example"><P style="display:none">Example(s):</P>
<p>This model would apply in the following example if the following
rules:</p>
<pre><code class="css">
<del>/* Note: HTML UAs may not respect these rules */ BODY</del><ins>p</ins> { display: inline }
<del>P</del><ins>span</ins> { display: block }
</code></pre>
<p>were used with this HTML document:</p>
<pre class="html-example"><code class="html">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML <del>4.0 Transitional//EN"></del><ins>4.01//EN"></ins>
<HEAD>
<TITLE>Anonymous text interrupted by a block</TITLE>
</HEAD>
<BODY>
<ins><P></ins>
<em>This is anonymous text before the <del>P. <P>This</del><ins>SPAN.</ins></em>
<ins><SPAN>This</ins> is the content of <del>P.</></del><ins>SPAN.</SPAN></ins>
<em>This is anonymous text after the <del>P.</del><ins>SPAN.</ins></em>
<ins></P></ins>
</BODY>
</code></pre>
<p>The <del>BODY</del><ins>P</ins> element contains a chunk (C1) of anonymous text followed
by a block-level element followed by another chunk (C2) of anonymous
text. The resulting boxes would be <del>an anonymous</del><ins>a</ins> block box <del>for</del><ins>representing the</ins> BODY,
containing an anonymous block box around C1, the <del>P</del><ins>SPAN</ins> block box, and
another anonymous block box around C2.
</p></div>
<p>The properties of anonymous boxes are inherited from the
enclosing non-anonymous box <del>(in</del><ins>(e.g., in</ins> the <del>example:</del><ins>example just below the subsection heading "Anonymous block boxes",</ins> the one for DIV).
Non-inherited properties have their initial value. For example,
the font of the anonymous box is inherited from the DIV, but the
margins will be 0.
</p>
<p>
<del>9.2.2 Inline-level</del><ins>Properties set on</ins> elements <del>and inline</del><ins>that cause anonymous block</ins> boxes <del>Inline-level elements are those elements of</del><ins>to be
generated still apply to</ins> the <del>source document that do not form new blocks</del><ins>boxes and content</ins> of <del>content;</del><ins>that element. For
example, if a border had been set on the P element in the above
example, the border would be drawn around C1 (open at the end of the
line) and C2 (open at the start of the line).</ins>
</p>
<p>
<ins>Some user agents have implemented borders on inlines containing
blocks in other ways, e.g., by wrapping such nested blocks inside
"anonymous line boxes" and thus drawing inline borders around such
boxes. As CSS1 and CSS2 did not define this behavior, CSS1-only and
CSS2-only user agents may implement this alternative model and still
claim conformance to this part of CSS 2.1. This does not apply to UAs
developed after this specification was released.</ins>
</p>
<p><ins>Anonymous block boxes are ignored when resolving percentage values
that would refer to it: the closest non-anonymous ancestor box is used
instead. For example, if the child of the anonymous block box inside
the DIV above needs to know the height of its containing block to
resolve a percentage height, then it will use the height of the
containing block formed by the DIV, not of the anonymous block box.</ins>
<h3><ins>9.2.2</ins> <a name="inline-boxes"><ins>Inline-level elements and inline boxes</ins></a></h3>
<p><span class="index-def" title="inline-level element">
<a name="inline-level"><dfn><ins>Inline-level
elements</ins></dfn></a></span> <ins>are those elements of the source document that
do not form new blocks of content;</ins> the content is distributed in lines
(e.g., emphasized pieces of text
within a paragraph, inline images,
etc.). <del>Several</del><ins>The following</ins> values of the <a href="visuren.html#propdef-display" class="noxref"><span
class="propinst-display">'display'</span></a> property make an element
<del>inline:</del><ins>inline-level:</ins> 'inline', 'inline-table', <del>'compact' and 'run-in' (part of the time; see compact</del>and <del>run-in boxes ).</del><ins>'inline-block'.</ins>
Inline-level elements generate <a name="x11"><span class="index-def"
title="inline-level box"><dfn> <del>inline</del><ins>inline-level</ins>
boxes</dfn></span></a> <del>. Inline</del><ins>, which are</ins> boxes <del>may</del><ins>that</ins> participate in <del>several</del><ins>an inline</ins>
formatting <del>contexts: Within a block box,</del><ins>context.</ins>
<p>An <span class="index-def" title="inline box"><a
name="inline-box"><dfn>inline
<del>boxes</del><ins>box</ins></dfn></a></span> <ins>is one that is both inline-level and whose
contents</ins> participate in <del>an</del><ins>its containing</ins> inline formatting <del>context .</del><ins>context.</ins> A
<del>compact inline box is given</del><ins>non-replaced element with</ins> a <del>position in the margin</del><ins>'display' value</ins> of <del>a block</del><ins>'inline' generates an
inline</ins> box.
<del>Marker</del><ins>Inline-level</ins> boxes <ins>that</ins> are <del>also given positions outside of a block box. Anonymous</del><ins>not</ins> inline boxes <del>In a document like this: <P>Some <EM>emphasized</em> text</P> The P generates a block box, with several</del><ins>(such as replaced
inline-level elements, inline-block elements, and inline-table
elements) are called</ins> <a name="x13"><span class="index-def" title="atomic
inline-level box"><dfn><ins>atomic inline-level boxes</ins></dfn></span></a> <ins>because
they participate in their inline formatting context as a single opaque
box.</ins>
<h4><ins>9.2.2.1</ins> <a name="anonymous"><ins>Anonymous inline boxes</ins></a></h4>
<p><ins>Any text that is directly contained inside a block container element (not
inside an inline element) must be treated as an anonymous inline
element.</ins>
<p><ins>In a document with HTML markup like this:</ins></p>
<div class="html-example">
<pre><code class="html">
<ins><p>Some <em>emphasized</em> text</p></ins>
</code></pre>
</div>
<p><ins>the</ins> <code><ins><p></ins></code> <ins>generates a block box, with several</ins> inline boxes inside
it. The box for "emphasized" is an inline box generated by an inline
element <del>(EM),</del><ins>(</ins><code><ins><em></ins></code><ins>),</ins> but the other boxes ("Some" and "text") are inline boxes generated by a block-level element <del>(P).</del><ins>(</ins><code><ins><p></ins></code><ins>).</ins> The latter are called <a name="x14"><span
class="index-def" title="anonymous inline boxes">anonymous inline
boxes</span></a>, because they <del>don't</del><ins>do not</ins> have an associated inline-level element.
</p>
<p>Such anonymous inline boxes inherit inheritable properties from
their block parent box. Non-inherited properties have their initial
value. In the example, the color of the anonymous <del>initial</del><ins>inline</ins> boxes is
inherited from the P, but the background is transparent.
</p>
<p>
<ins>White space content that would subsequently be collapsed away according to the</ins> <a href="text.html#propdef-white-space" class="noxref"><span class="propinst-white-space"><ins>'white-space'</ins></span></a> <ins>property does not generate any anonymous inline boxes.</ins>
</p>
<p>If it is clear from the context which type of anonymous box is
meant, both anonymous inline boxes and anonymous block boxes are
simply called anonymous boxes in this specification.
</p>
<p>There are more types of anonymous boxes that arise when formatting
<a href="tables.html#anonymous-boxes">tables</a>.
</p>
<h3>9.2.3 <a name="run-in"> <del>Compact</del><ins>Run-in</ins> boxes</a></h3>
<p> <del>A compact box behaves</del><ins>[This section exists so that the section numbers are the same</ins> as <del>follows: If a block box (that does not float and is</del><ins>in
previous drafts. Run-in boxes are</ins> not <del>absolutely positioned ) follows the compact box,</del><ins>part of CSS 2.1.]</ins>
<h3><ins>9.2.4</ins> <a name="display-prop">The</a> <a href="visuren.html#propdef-display" class="noxref"><span
class="propinst-display"> <del>compact box is formatted like a one-line</del><ins>'display'</ins></span></a> <ins>property</ins></h3>
<div class="propdef">
<dl><dt>
<span class="index-def" title="'display'"><a name="propdef-display" class="propdef-title"><strong><ins>'display'</ins></strong></a></span>
<dd>
<table class="propinfo" cellspacing=0 cellpadding=0>
<tr valign=baseline><td><em><ins>Value:</ins></em><ins> </ins><td>inline <del>box. The resulting box width is compared to one of</del><ins>| block | list-item | run-in | inline-block |
table | inline-table | table-row-group | table-header-group |
table-footer-group | table-row | table-column-group | table-column |
table-cell | table-caption | none |</ins> <a href="cascade.html#value-def-inherit" class="noxref"><span class="value-inst-inherit"><ins>inherit</ins></span></a>
<tr valign=baseline><td><em><ins>Initial:</ins></em><ins> </ins><td><ins>inline</ins>
<tr valign=baseline><td><em><ins>Applies to:</ins></em><ins> </ins><td><ins>all elements</ins>
<tr valign=baseline><td><em><ins>Inherited:</ins></em><ins> </ins><td><ins>no</ins>
<tr valign=baseline><td><em><ins>Percentages:</ins></em><ins> </ins><td><ins>N/A</ins>
<tr valign=baseline><td><em><ins>Media:</ins></em><ins> </ins><td><a href="media.html#all-media-group" class="noxref"><ins>all</ins></a>
<tr valign=baseline><td><em><ins>Computed value:</ins></em><ins> </ins><td><ins>see text</ins>
</table>
</dl>
</div>
<p>The <del>side margins</del><ins>values</ins> of <ins>this property have</ins> the <ins>following meanings:</ins></p>
<dl>
<dt><span class="index-def" title="'block', definition of"><a
name="value-def-block"><strong><ins>block</ins></strong></a></span>
</dt>
<dd><ins>This value causes an element to generate a</ins> block box.
</dd>
<dt><span class="index-def" title="'inline-block', definition of"><a
name="value-def-inline-block"><strong><ins>inline-block</ins></strong></a></span>
</dt>
<dd><ins>This value causes an element to generate an inline-level block
container.</ins>
The <del>choice</del><ins>inside</ins> of <del>left or right margin</del><ins>an inline-block</ins> is <del>determined by the 'direction' specified for the element producing the containing</del><ins>formatted as a</ins> block <del>for the compact box</del><ins>box,</ins> and <del>following box. If</del>the
<del>inline box width</del><ins>element itself</ins> is <del>less than or equal</del><ins>formatted as an atomic inline-level box.</ins>
</dd>
<dt><span class="index-def" title="'inline', definition of"><a
name="value-def-inline"><strong><ins>inline</ins></strong></a></span>
</dt>
<dd><ins>This value causes an element</ins> to <del>the margin, the</del><ins>generate one or more</ins> inline <del>box is given a position</del><ins>boxes.</ins>
</dd>
<dt><span class="index-def" title="'list-item', definition of"><a
name="value-def-list-item"><strong><ins>list-item</ins></strong></a></span>
</dt>
<dd><ins>This value causes an element (e.g., LI</ins> in <del>the margin as described immediately below. Otherwise, the compact box becomes</del><ins>HTML) to generate</ins> a
<ins>principal</ins> block <del>box. The compact</del>box <del>is given</del><ins>and</ins> a <del>position in the margin as follows: it is outside (to the left or right) of the first line box</del><ins>marker box. For information about
lists and examples</ins> of <ins>list formatting, please consult</ins> the <del>block, but it affects the calculation of that line box's height</del><ins>section on</ins>
<a href="generate.html#lists"><ins>lists</ins></a>.
</dd>
<dt><strong> <del>The 'vertical-align' property of the compact box determines the vertical position of the compact box relative</del><ins>none</ins></strong></dt>
<dd><a name="x20"><span class="index-def" title="'none'::as display value"><ins>This
value</ins></span></a> <ins>causes an element</ins> to <del>that line box. The horizontal position of the compact box is always</del><ins>not appear</ins> in the <a
href="intro.html#formatting-structure"> <del>margin of</del><ins>formatting structure</ins></a> <ins>(i.e.,
in visual media</ins> the <del>block box. An</del>element <del>that cannot be formatted</del><ins>generates no boxes and has no effect</ins> on
<del>one line</del><ins>layout). Descendant elements do not generate any boxes either; the
element and its content are removed from the formatting structure
entirely. This behavior</ins> <strong>cannot</strong> be <del>placed in</del><ins>overridden by
setting</ins> the <a href="visuren.html#propdef-display" class="noxref"><span class="propinst-display"> <del>margin of</del><ins>'display'</ins></span></a> <ins>property
on</ins> the <del>following block. For example, a 'compact' element in HTML</del><ins>descendants.</ins>
<p><ins>Please note</ins> that <del>contains a BR element will always be formatted as</del>a <del>block</del><ins>display of 'none' does not create an invisible
box; it creates no</ins> box <del>(assuming the default style for BR, which inserts a newline). For placing multi-line texts</del><ins>at all. CSS includes mechanisms that enable an
element to generate boxes</ins> in the <del>margin, the 'float' property is often more appropriate.</del><ins>formatting structure that affect
formatting but are not visible themselves. Please consult</ins> the <del>following example illustrates a compact box. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN"> <HTML> <HEAD> <TITLE>A compact box example</TITLE> <STYLE type="text/css"> DT { display: compact } DD { margin-left: 4em } </STYLE> </HEAD> <BODY> <DL> <DT>Short <DD><P>Description goes here. <DT>too long</del><ins>section
on</ins> <a href="visufx.html#visibility"><ins>visibility</ins></a> for <del>the margin <DD><P>Description goes here. </DL> </BODY> </HTML></del><ins>details.</ins>
</p>
</dd>
<dt><span class="index-def" title="'run-in', definition of"><a
name="value-def-run-in"><strong><ins>run-in</ins></strong></a></span>
</dt>
<dd>This <del>example might be formatted as: short Description goes here too long</del><ins>value creates either block or
inline boxes, depending on context.
'Run-in' is defined in CSS level 3 (see</ins> <a
href="/TR/css3-box"><ins>CSS basic box model</ins></a><ins>). It is not required</ins> for
<del>the margin Description goes here The 'text-align' property can be used</del><ins>conformance</ins> to <del>align the compact</del><ins>level 2.</ins>
</dd>
<dt>
<a href="tables.html#value-def-table" class="noxref"><span class="value-inst-table"><ins>table</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-inline-table" class="noxref"><span class="value-inst-inline-table"><ins>inline-table</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-table-row-group" class="noxref"><span class="value-inst-table-row-group"><ins>table-row-group</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-table-column" class="noxref"><span class="value-inst-table-column"><ins>table-column</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-table-column-group" class="noxref"><span class="value-inst-table-column-group"><ins>table-column-group</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-table-header-group" class="noxref"><span class="value-inst-table-header-group"><ins>table-header-group</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-table-footer-group" class="noxref"><span class="value-inst-table-footer-group"><ins>table-footer-group</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-table-row" class="noxref"><span class="value-inst-table-row"><ins>table-row</ins></span></a><ins>,</ins>
<a href="tables.html#value-def-table-cell" class="noxref"><span class="value-inst-table-cell"><ins>table-cell</ins></span></a><ins>, and</ins>
<a href="tables.html#value-def-table-caption" class="noxref"><span class="value-inst-table-caption"><ins>table-caption</ins></span></a>
</dt>
<dd><ins>These values cause an</ins> element <del>inside the margin: against the left edge of the margin ('left'), against the right edge ('right'), or centered</del><ins>to behave like a table element
(subject to restrictions described</ins> in the <del>margin ('center').</del><ins>chapter on</ins> <a
href="tables.html"><ins>tables</ins></a><ins>).</ins>
</dd>
</dl>
<p>The <ins>computed</ins> value <del>'justify' doesn't apply, and</del>is <del>handled</del><ins>the same</ins> as <del>either 'left' or 'right', depending on</del>the <del>'direction' of</del><ins>specified value, except for
positioned and floating elements (see</ins> <a
href="#dis-pos-flo"><ins>Relationships between 'display', 'position', and
'float'</ins></a><ins>) and for</ins> the <del>block-level element in whose margin</del><ins>root element.
For</ins> the <del>compact element is formatted. ('left' if</del><ins>root element,</ins> the <del>direction is 'ltr', 'right' if it</del><ins>computed value</ins> is <del>'rtl'.) Please consult</del><ins>changed as described in</ins>
the section on <del>generated content for information about how compact boxes interact with generated content. 9.2.4 Run-in boxes A run-in box behaves as follows: If a block box (that does not float and is not absolutely positioned ) follows the run-in box,</del>the <a href="#dis-pos-flo"> <del>run-in box becomes</del><ins>relationships between 'display', 'position', and 'float'</ins></a><ins>.</ins>
</p>
<p><ins>Note that although</ins> the <a href="about.html#initial-value"> <del>first inline box</del><ins>initial
value</ins></a> of <a href="visuren.html#propdef-display" class="noxref"><span class="propinst-display"><ins>'display'</ins></span></a> <ins>is
'inline', rules in</ins> the <del>block box. Otherwise,</del><ins>user agent'
E88C
;s</ins> <a
href="cascade.html#default-style-sheet"><ins>default style sheet</ins></a> <ins>may</ins> <a
href="cascade.html"><ins>override</ins></a> <ins>this value. See</ins> the <a
href="sample.html"> <del>run-in box becomes a block box. A 'run-in' box is useful</del><ins>sample style sheet</ins></a> for <del>run-in headers, as in this example: <!DOCTYPE HTML PUBLIC "-//W3C//DTD</del>HTML <del>4.0//EN"> <HTML> <HEAD> <TITLE>A run-in box example</TITLE> <STYLE type="text/css"> H3</del><ins>4 in the
appendix.</ins>
</p>
<div class="example"><P style="display:none"><ins>Example(s):</ins></P>
<p><ins>Here are some examples of the</ins> <a href="visuren.html#propdef-display" class="noxref"><span
class="propinst-display"><ins>'display'</ins></span></a> <ins>property:</ins>
</p>
<pre><code class="css">
<ins>p</ins> { display: <del>run-in</del><ins>block</ins> }
<del></STYLE> </HEAD> <BODY> <H3>A run-in heading.</H3> <P>And</del><ins>em { display: inline }
li { display: list-item }
img { display: none } /* Do not display images */</ins>
</code></pre>
</div>
<h2><ins>9.3</ins> <a name="positioning-scheme"><ins>Positioning schemes</ins></a></h2>
<p><ins>In CSS 2.1,</ins> a <del>paragraph of text that follows it. </BODY> </HTML> This example might</del><ins>box may</ins> be <del>formatted as: A run-in heading.</del><ins>laid out according to three</ins> <a name="x22"><span
class="index-def" title="positioning scheme"><dfn><ins>positioning
schemes:</ins></dfn></span></a></p>
<ol>
<li><a href="#normal-flow"><ins>Normal flow</ins></a><ins>. In CSS 2.1, normal
flow includes</ins> <a href="#block-formatting"><ins>block formatting</ins></a>
<ins>of block-level boxes,</ins>
<a href="#inline-formatting"><ins>inline formatting</ins></a>
<ins>of inline-level boxes,</ins> and <a
href="#relative-positioning"> <del>a paragraph</del><ins>relative positioning</ins></a> of
<del>text that follows it.</del><ins>block-level and inline-level boxes.</ins>
</li>
<li><a href="#floats"><ins>Floats</ins></a><ins>. In</ins> the <del>properties</del><ins>float model,
a box is first laid out according to the normal flow, then
taken out</ins> of the <del>run-in element are inherited from its parent in</del><ins>flow and shifted
to</ins> the <del>source tree, not from</del><ins>left or right as far as possible. Content may
flow along</ins> the <del>block</del><ins>side of a float.</ins>
</li>
<li><a href="#absolute-positioning"><ins>Absolute positioning</ins></a><ins>.
In the absolute positioning model, a</ins> box <del>it visually becomes part of. Please consult</del><ins>is removed from</ins>
the <del>section</del><ins>normal flow entirely (it has no impact</ins> on <del>generated content for information about how run-in boxes interact</del><ins>later siblings)
and assigned a position</ins> with <del>generated content. 9.2.5</del><ins>respect to a containing block.</ins>
</li>
</ol>
<p><ins>An element is called</ins> <dfn><a name="x23"><span class="index-def"><ins>out of
flow</ins></span></a></dfn> <ins>if it is floated, absolutely positioned, or is</ins> the
<del>'display' property 'display' Value: inline | block | list-item | run-in | compact | marker | table | inline-table | table-row-group | table-header-group | table-footer-group | table-row | table-column-group | table-column</del><ins>root element. An element is called</ins> <dfn><a name="x24"><span
class="index-def"><ins>in-flow</ins></span></a></dfn> <ins>if it is not out-of-flow. The</ins>
<dfn><a name="x25"><span class="index-def"><ins>flow of an element</ins></span></a></dfn>
<var><ins>A</ins></var> <ins>is the set consisting of</ins> <var><ins>A</ins></var> <ins>and all in-flow
elements whose nearest out-of-flow ancestor is</ins> <var><ins>A</ins></var><ins>.</ins>
<div class="note">
<em><strong><ins>Note.</ins></strong>
<ins>CSS 2.1's positioning schemes help authors make their documents
more accessible by allowing them to avoid mark-up tricks
(e.g., invisible images) used for layout effects.</ins>
</em>
</div>
<h3><ins>9.3.1</ins> <a name="choose-position"><ins>Choosing a positioning scheme:</ins></a> <a href="visuren.html#propdef-position" class="noxref"><span
class="propinst-position"><ins>'position'</ins></span></a> <ins>property</ins></h3>
<p><ins>The</ins> <a href="visuren.html#propdef-position" class="noxref"><span class="propinst-position"><ins>'position'</ins></span></a> <ins>and</ins> <a href="visuren.html#propdef-float" class="noxref"><span
class="propinst-float"><ins>'float'</ins></span></a> <ins>properties determine which
of the CSS 2.1 positioning algorithms is used to calculate
the position of a box.</ins>
</p>
<div class="propdef">
<dl><dt>
<span class="index-def" title="'position'"><a name="propdef-position" class="propdef-title"><strong><ins>'position'</ins></strong></a></span>
<dd>
<table class="propinfo" cellspacing=0 cellpadding=0>
<tr valign=baseline><td><em><ins>Value:</ins></em><ins> </ins><td><ins>static</ins> | <del>table-cell</del><ins>relative</ins> | <del>table-caption</del><ins>absolute</ins> | <del>none</del><ins>fixed</ins> | <a href="cascade.html#value-def-inherit" class="noxref"><span class="value-inst-inherit">inherit</span></a>
<tr valign=baseline><td><em>Initial:</em> <td> <del>inline</del><ins>static</ins>
<tr valign=baseline><td><em>Applies to:</em> <td>all elements
<tr valign=baseline><td><em>Inherited:</em> <td>no
<tr valign=baseline><td><em>Percentages:</em> <td>N/A
<tr valign=baseline><td><em>Media:</em> <td><a href="media.html#visual-media-group" class="noxref"> <del>all</del><ins>visual</ins></a>
<tr valign=baseline><td><em><ins>Computed value:</ins></em><ins> </ins><td><ins>as specified</ins>
</table>
</dl>
</div>
<p>The values of this property have the following meanings:</p>
<dl>
<dt><strong> <del>block This value causes an element to generate</del><ins>static</ins></strong></dt>
<dd><ins>The box is</ins> a <del>principal block box. inline This value causes an element</del><ins>normal box, laid out according</ins> to <del>generate one or more inline boxes. list-item This value causes an element (e.g., LI</del><ins>the</ins> <a
href="#normal-flow"><ins>normal flow</ins></a><ins>. The</ins>
<a href="visuren.html#propdef-top" class="noxref"><span class="propinst-top"><ins>'top'</ins></span></a><ins>,</ins>
<a href="visuren.html#propdef-right" class="noxref"><span class="propinst-right"><ins>'right'</ins></span></a><ins>,</ins>
<a href="visuren.html#propdef-bottom" class="noxref"><span class="propinst-bottom"><ins>'bottom'</ins></span></a><ins>,
and</ins> <a href="visuren.html#propdef-left" class="noxref"><span class="propinst-left"><ins>'left'</ins></span></a>
<ins>properties do not apply.</ins>
</dd>
<dt><strong><ins>relative</ins></strong></dt>
<dd><ins>The box's position is calculated according to the</ins> <a
href="#normal-flow"><ins>normal flow</ins></a> <ins>(this is called the position</ins> in
<del>HTML)</del><ins>normal flow). Then the box is offset</ins> <a
href="#relative-positioning"><ins>relative</ins></a> to <del>generate</del><ins>its normal position. When</ins>
a <del>principal block</del>box <del>and a list-item inline box. For information about lists and examples</del><ins>B is relatively positioned, the position</ins> of <del>list formatting, please consult</del>the <del>section on lists . marker This value declares generated content before or after a</del><ins>following</ins> box <del>to be a marker. This value should only be used with :before and :after pseudo-elements attached to block-level elements. In other cases, this value</del>is
<del>interpreted</del><ins>calculated</ins> as <del>'inline'. Please consult</del><ins>though B were not offset.</ins> The <del>section</del><ins>effect of 'position:relative'</ins> on <del>markers for more information. none This value causes an element</del><ins>table-row-group, table-header-group, table-footer-group, table-row, table-column-group, table-column, table-cell, and table-caption elements is undefined.</ins>
</dd>
<dt><strong><ins>absolute</ins></strong></dt>
<dd> <ins>The box's position (and possibly size) is specified
with the</ins> <a href="visuren.html#propdef-top" class="noxref"><span class="propinst-top"><ins>'top'</ins></span></a><ins>,</ins>
<a href="visuren.html#propdef-right" class="noxref"><span class="propinst-right"><ins>'right'</ins></span></a><ins>,</ins>
<a href="visuren.html#propdef-bottom" class="noxref"><span class="propinst-bottom"><ins>'bottom'</ins></span></a><ins>, and</ins>
<a href="visuren.html#propdef-left" class="noxref"><span class="propinst-left"><ins>'left'</ins></span></a>
<ins>properties.
These properties specify offsets with respect</ins> to <del>generate no boxes in</del>the <del>formatting structure (i.e.,</del><ins>box's</ins>
<a href="#containing-block"><ins>containing block</ins></a><ins>. Absolutely
positioned boxes are taken out of</ins> the <del>element has</del><ins>normal flow. This means
they have</ins> no <del>effect</del><ins>impact</ins> on <del>layout). Descendant elements</del><ins>the layout of later siblings. Also,
though</ins> <a href="#absolutely-positioned"><ins>absolutely positioned</ins></a>
<ins>boxes have margins, they</ins>
do not <a href="box.html#collapsing-margins"> <del>generate</del><ins>collapse</ins></a>
<ins>with</ins> any <del>boxes either; this behavior cannot be overridden by setting</del><ins>other margins.</ins>
</dd>
<dt><strong><ins>fixed</ins></strong></dt>
<dd> The <del>'display' property on</del><ins>box's position is calculated according to the 'absolute'
model, but in addition,</ins> the <del>descendants. Please note that a display of 'none' does not create an invisible box; it creates no</del>box <del>at all. CSS includes mechanisms that enable an element</del><ins>is</ins> <a
href="#fixed-positioning"><ins>fixed</ins></a> <ins>with respect</ins> to <del>generate boxes in</del><ins>some reference.
As with</ins> the <del>formatting structure that affect formatting but are</del><ins>'absolute' model, the box's margins do</ins> not <del>visible themselves. Please consult</del><ins>collapse with any other margins.
In</ins> the <del>section on visibility for details. run-in</del><ins>case of handheld, projection, screen, tty,</ins> and <del>compact These values create either block or inline boxes, depending on context. Properties apply</del><ins>tv media types,
the box is fixed with respect</ins> to <del>run-in</del><ins>the</ins> <a href="#viewport"><ins>viewport</ins></a>
and <del>compact boxes based</del><ins>does not move when
scrolled. In the case of the print media type, the box is rendered</ins> on <del>their final status (inline-level or block-level). For example,</del><ins>every page, and is fixed with respect to</ins> the <del>'white-space' property only applies</del><ins>page box, even</ins> if the <del>box becomes a block box. table , inline-table , table-row-group , table-column , table-column-group , table-header-group , table-footer-group , table-row , table-cell , and table-caption These values cause an element to behave like</del><ins>page is seen through</ins> a <a href="#viewport"> <del>table element (subject to restrictions described in the chapter on tables ). Note that although</del><ins>viewport</ins></a>
<ins>(in</ins> the <del>initial value</del><ins>case</ins> of <del>'display'</del><ins>a print-preview, for example). For other media
types, the presentation</ins> is <del>'inline', rules</del><ins>undefined.
Authors may wish to specify 'fixed'</ins> in <del>the user agent's default style sheet</del><ins>a
media-dependent way. For instance, an author</ins> may <del>override this value. See</del><ins>want a box to remain
at</ins> the <del>sample style sheet for HTML 4.0 in</del><ins>top of</ins> the <a href="#viewport"> <del>appendix. Example(s): Here are some examples</del><ins>viewport</ins></a> <ins>on the screen, but
not at the top</ins> of <ins>each printed page.</ins> The <del>'display' property: P</del><ins>two specifications may be
separated by using an</ins> <a href="media.html#at-media-rule"><ins>@media
rule</ins></a><ins>, as in:</ins>
<div class="example"><P style="display:none"><ins>Example(s):</ins></P>
<pre><code class="css">
<ins>@media screen</ins> {
<del>display: block } EM</del><ins>h1#first</ins> { <del>display: inline</del><ins>position: fixed</ins> }
<del>LI { display: list-item</del>}
<del>IMG</del><ins>@media print</ins> {
<del>display: none</del><ins>h1#first { position: static</ins> }
<del>/* Don't display images */ Conforming HTML</del><ins>}</ins>
</code></pre>
</div>
<p><ins>UAs must not paginate the content of fixed boxes.</ins> <span
class="note"><ins>Note that UAs may print invisible content in other
ways. See</ins> <a href="page.html#outside-page-box"><ins>"Content outside the
page box"</ins></a> <ins>in chapter 13.</ins></span>
</dd>
</dl>
<p>
User agents may <del>ignore</del><ins>treat position as 'static' on</ins> the <del>'display' property. 9.3 Positioning schemes In CSS2, a</del><ins>root element.</ins>
</p>
<h3><ins>9.3.2</ins> <a name="position-props">Box <del>may</del><ins>offsets</ins></a><ins>:</ins> <a href="visuren.html#propdef-top" class="noxref"><span
class="propinst-top"><ins>'top'</ins></span></a><ins>,</ins> <a href="visuren.html#propdef-right" class="noxref"><span
class="propinst-right"><ins>'right'</ins></span></a><ins>,</ins> <a href="visuren.html#propdef-bottom" class="noxref"><span
class="propinst-bottom"><ins>'bottom'</ins></span></a><ins>,</ins> <a href="visuren.html#propdef-left" class="noxref"><span
class="propinst-left"><ins>'left'</ins></span></a></h3>
<p><ins>An element is said to</ins> be <span class="index-def" title="positioned
element/box"><a name="positioned-element"><dfn><ins>positioned</ins></dfn></a></span>
<ins>if its</ins> <a href="visuren.html#propdef-position" class="noxref"><span class="propinst-position"><ins>'position'</ins></span></a> <ins>property has
a value other than 'static'. Positioned elements generate
positioned boxes,</ins> laid out according to <del>three positioning schemes: Normal flow . In CSS2, normal flow includes block formatting of block boxes, inline formatting of inline boxes, relative positioning</del><ins>four properties:</ins></p>
<div class="propdef">
<dl><dt>
<span class="index-def" title="'top'"><a name="propdef-top" class="propdef-title"><strong><ins>'top'</ins></strong></a></span>
<dd>
<table class="propinfo" cellspacing=0 cellpadding=0>
<tr valign=baseline><td><em><ins>Value:</ins></em><ins> </ins><td><a href="syndata.html#value-def-length" class="noxref"><span class="value-inst-length"><ins><length></ins></span></a> <ins>|</ins> <a href="syndata.html#value-def-percentage" class="noxref"><span class="value-inst-percentage"><ins><percentage></ins></span></a> <ins>| auto |</ins> <a href="cascade.html#value-def-inherit" class="noxref"><span class="value-inst-inherit"><ins>inherit</ins></span></a>
<tr valign=baseline><td><em><ins>Initial:</ins></em><ins> </ins><td><ins>auto</ins>
<tr valign=baseline><td><em><ins>Applies to:</ins></em><ins> </ins><td><ins>positioned elements</ins>
<tr valign=baseline><td><em><ins>Inherited:</ins></em><ins> </ins><td><ins>no</ins>
<tr valign=baseline><td><em><ins>Percentages:</ins></em><ins> </ins><td><ins>refer to height</ins> of <ins>containing</ins> block
<tr valign=baseline><td><em> <del>or inline boxes, and positioning of compact and run-in boxes. Floats . In the float model,</del><ins>Media:</ins></em><ins> </ins><td><a href="media.html#visual-media-group" class="noxref"><ins>visual</ins></a>
<tr valign=baseline><td><em><ins>Computed value:</ins></em><ins> </ins><td><ins>if
specified as</ins> a <del>box is first laid out according to the normal flow, then taken out of the flow and shifted to</del><ins>length,</ins> the <del>left or right</del><ins>corresponding absolute length; if
specified</ins> as <ins>a percentage, the specified value; otherwise, 'auto'.</ins>
</table>
</dl>
</div>
<p><ins>This property specifies how</ins> far <del>as possible. Content may flow along</del><ins>an</ins> <a
href="#absolutely-positioned"><ins>absolutely positioned</ins></a> <ins>box's top
margin edge is offset below</ins> the <del>side</del><ins>top edge</ins> of <del>a float. Absolute positioning</del><ins>the box's</ins> <a
href="#containing-block"><ins>containing block</ins></a>. <del>In</del><ins>For relatively
positioned boxes,</ins> the <del>absolute positioning model, a box</del><ins>offset</ins> is <del>removed from the normal flow entirely (it has no impact on later siblings) and assigned a position</del>with respect to <del>a containing block. Note. CSS2's positioning schemes help authors make their documents more accessible by allowing them to avoid mark-up tricks (e.g., invisible images) used for layout effects. 9.3.1 Choosing a positioning scheme: 'position' property</del>the <del>'position' and 'float' properties determine which</del><ins>top edges</ins> of the
<del>CSS2 positioning algorithms</del><ins>box itself (i.e., the box</ins> is <del>used to calculate</del><ins>given a position in</ins> the <ins>normal flow, then
offset from that</ins> position <del>of a box. 'position'</del><ins>according to these properties).</ins>
</p>
<div class="propdef">
<dl><dt>
<span class="index-def" title="'right'"><a name="propdef-right" class="propdef-title"><strong><ins>'right'</ins></strong></a></span>
<dd>
<table class="propinfo" cellspacing=0 cellpadding=0>
<tr valign=baseline><td><em>Value:</em> <td><a href="syndata.html#value-def-length" class="noxref"><span class="value-inst-length"> <del>static | relative</del><ins><length></ins></span></a> | <a href="syndata.html#value-def-percentage" class="noxref"><span class="value-inst-percentage"> <del>absolute</del><ins><percentage></ins></span></a> | <del>fixed</del><ins>auto</ins> | <a href="cascade.html#value-def-inherit" class="noxref"><span class="value-inst-inherit">inherit</span></a>
<tr valign=baseline><td><em>Initial:</em> <td> <del>static</del><ins>auto</ins>
<tr valign=baseline><td><em>Applies to:</em> <td> <del>all elements, but not to generated content</del><ins>positioned elements</ins>
<tr valign=baseline><td><em>Inherited:</em> <td>no
<tr valign=baseline><td><em>Percentages:</em> <td> <del>N/A</del><ins>refer to width of containing block</ins>
<tr valign=baseline><td><em>Media:</em> <td><a href="media.html#visual-media-group" class="noxref">visual</a>
<tr valign=baseline><td><em><ins>Computed value:</ins></em><ins> </ins><td><ins>if
specified as a length,</ins> the <del>values of this property have</del><ins>corresponding absolute length; if
specified as a percentage,</ins> the <del>following meanings: static The box is</del><ins>specified value; otherwise,
'auto'.</ins>
</table>
</dl>
</div>
<p><ins>Like 'top', but specifies how far</ins> a <del>normal box, laid out according to the normal flow . The 'left' and 'top' properties do not apply. relative The</del>box's <del>position is calculated according to the normal flow (this is called the position in normal flow). Then the box</del><ins>right margin edge</ins> is
offset <del>relative</del>to <del>its normal position. When a box B is relatively positioned,</del>the <del>position</del><ins>left</ins> of the <del>following box is calculated as though B were not offset. absolute</del><ins>right edge of</ins> the box's <a
href="#containing-block"> <del>position (and possibly size) is specified with</del><ins>containing block</ins></a><ins>. For relatively
positioned boxes,</ins> the <del>'left' , 'right' , 'top' , and 'bottom' properties. These properties specify offsets</del><ins>offset is</ins> with respect to the <del>box's containing block . Absolutely positioned boxes are taken out</del><ins>right edge</ins> of the
<del>normal flow. This means they have</del><ins>box itself.</ins>
</p>
<div class="propdef">
<dl><dt>
<span class="index-def" title="'bottom'"><a name="propdef-bottom" class="propdef-title"><strong><ins>'bottom'</ins></strong></a></span>
<dd>
<table class="propinfo" cellspacing=0 cellpadding=0>
<tr valign=baseline><td><em><ins>Value:</ins></em><ins> </ins><td><a href="syndata.html#value-def-length" class="noxref"><span class="value-inst-length"><ins><length></ins></span></a> <ins>|</ins> <a href="syndata.html#value-def-percentage" class="noxref"><span class="value-inst-percentage"><ins><percentage></ins></span></a> <ins>| auto |</ins> <a href="cascade.html#value-def-inherit" class="noxref"><span class="value-inst-inherit"><ins>inherit</ins></span></a>
<tr valign=baseline><td><em><ins>Initial:</ins></em><ins> </ins><td><ins>auto</ins>
<tr valign=baseline><td><em><ins>Applies to:</ins></em><ins> </ins><td><ins>positioned elements</ins>
<tr valign=baseline><td><em><ins>Inherited:</ins></em><ins> </ins><td>no
<tr valign=baseline><td><em> <del>impact on the layout</del><ins>Percentages:</ins></em><ins> </ins><td><ins>refer to height</ins> of <del>later siblings. Also, though absolutely positioned boxes have margins, they do not collapse with any other margins. fixed</del><ins>containing block</ins>
<tr valign=baseline><td><em><ins>Media:</ins></em><ins> </ins><td><a href="media.html#visual-media-group" class="noxref"><ins>visual</ins></a>
<tr valign=baseline><td><em><ins>Computed value:</ins></em><ins> </ins><td><ins>if
specified as a length,</ins> the <del>box's position is calculated according to</del><ins>corresponding absolute length; if
specified as a percentage,</ins> the <del>'absolute' model,</del><ins>specified value; otherwise, 'auto'.</ins>
</table>
</dl>
</div>
<p><ins>Like 'top',</ins> but <del>in addition, the box</del><ins>specifies how far a box's bottom margin edge</ins> is
<del>fixed with respect to some reference. In</del><ins>offset above</ins> the <del>case</del><ins>bottom</ins> of <del>continuous media ,</del>the <del>box</del><ins>box's</ins> <a
href="#containing-block"><ins>containing block</ins></a><ins>. For relatively
positioned boxes, the offset</ins> is <del>fixed</del>with respect to the <del>viewport (and doesn't move when scrolled). In the case</del><ins>bottom edge</ins> of <del>paged media ,</del>the
box <del>is fixed with respect to the page, even if that page is seen through a viewport (in the case of a print-preview, for example). Authors may wish to specify 'fixed' in a media-dependent way. For instance, an author may want a box to remain at the top of the viewport on the screen, but not at the top of each printed page. The two specifications may be separated by using an @media rule , as in: Example(s): @media screen { H1#first { position: fixed } } @media print { H1#first { position: static } } 9.3.2 Box offsets : 'top' , 'right' , 'bottom' ,</del><ins>itself.</ins>
</p>
<div class="propdef">
<dl><dt>
<span class="index-def" title="'left'"><a name="propdef-left" class="propdef-title"><strong>'left'</strong></a></span>
<dd>
<table class="propinfo" cellspacing=0 cellpadding=0>
<tr valign=baseline><td><em> <del>An element is said to be positioned if its 'position' property has a value other than 'static'. Positioned elements generate positioned boxes, laid out according to four properties: 'top'</del>Value:</em> <td><a href="syndata.html#value-def-length" class="noxref"><span class="value-inst-length"><length></span></a> | <a href="syndata.html#value-def-percentage" class="noxref"><span class="value-inst-percentage"><percentage></span></a> | auto | <a href="cascade.html#value-def-inherit" class="noxref"><span class="value-inst-inherit">inherit</span></a>
<tr valign=baseline><td><em>Initial:</em> <td>auto
<tr valign=baseline><td><em>Applies to:</em> <td>positioned elements
<tr valign=baseline><td><em>Inherited:</em> <td>no
<tr valign=baseline><td><em>Percentages:</em> <td>refer to <del>height</del><ins>width</ins> of containing block
<tr valign=baseline><td><em>Media:</em> <td><a href="media.html#visual-media-group" class="noxref">visual</a>
<tr valign=baseline><td><em> <del>This property</del><ins>Computed value:</ins></em><ins> </ins><td><ins>if
specified as a length, the corresponding absolute length; if
specified as a percentage, the specified value; otherwise,
'auto'.</ins>
</table>
</dl>
</div>
<p><ins>Like 'top', but</ins> specifies how far a box's <del>top content</del><ins>left margin</ins> edge is
offset <del>below</del><ins>to</ins> the <del>top</del><ins>right of the left</ins> edge of the box's <a
href="#containing-block">containing block</a>. <del>'right' Value: <length> | <percentage> | auto | inherit Initial: auto Applies to: </del><ins>For relatively</ins>
positioned <del>elements Inherited: no Percentages: refer to width of containing block Media: visual This property specifies how far a box's right content edge is</del><ins>boxes, the</ins> offset <ins>is with respect</ins> to the left <del>of the right</del>edge of the
<del>box's containing block . 'bottom' Value: </del><ins>box itself.</ins>
</p>
<p><ins>The values for the four properties have the following meanings:</ins></p>
<dl>
<dt><strong><a href="syndata.html#value-def-length" class="noxref"><span class="value-inst-length"><length></span></a></strong></dt>
<dd> <del>| <percentage> | auto | inherit Initial: auto Applies to: positioned elements Inherited: no Percentages: refer to height of containing block Media: visual This property specifies how far a box's bottom content edge is offset above the bottom of the box's containing block . 'left' Value: <length> | <percentage> | auto | inherit Initial: auto Applies to: positioned elements Inherited: no Percentages: refer to width of containing block Media: visual This property specifies how far a box's left content edge is offset to the right of the left edge of the box's containing block . The values for the four properties have the following meanings: <length> The offset is a fixed distance from the reference edge.</del><ins>The offset is a fixed distance from the reference edge. Negative values are allowed.</ins>
</dd>
<dt><strong><a href="syndata.html#value-def-percentage" class="noxref"><span class="value-inst-percentage"><percentage></span></a></strong></dt>
<dd>The offset is a percentage of the containing block's width (for <a href="visuren.html#propdef-left" class="noxref"><span class="propinst-left">'left'</span></a> or <a href="visuren.html#propdef-right" class="noxref"><span
class="propinst-right">'right'</span></a>) or height (for <a href="visuren.html#propdef-top" class="noxref"><span
class="propinst-top">'top'</span></a> and <a href="visuren.html#propdef-bottom" class="noxref"><span
class="propinst-bottom">'bottom'</span></a>). <del>For 'top' and 'bottom', if the height of the containing block is not specified explicitly (i.e., it depends on content height), the percentage value is interpreted like 'auto'.</del><ins>Negative values are allowed.</ins>
</dd>
<dt><strong>auto</strong></dt>
<dd><ins>For non-replaced elements,</ins> the effect of this value
depends on which of related properties have the value 'auto' as
well. See the sections on the
<a href="visudet.html#abs-non-replaced-width">width</a>
and <a href="visudet.html#abs-non-replaced-height">height</a>
of <a href="#absolutely-positioned">absolutely positioned</a>,
non-replaced elements for details. For <del>absolutely positioned boxes, the offsets are with respect to the box's containing block . For relatively positioned boxes,</del><ins>replaced elements,</ins> the
<del>offsets are with respect to</del><ins>effect of this value depends only on</ins> the <del>outer edges</del><ins>intrinsic dimensions</ins> of the
<del>box itself (i.e.,</del><ins>replaced content. See</ins> the <del>box is given a position in</del><ins>sections on</ins> the <a
href="visudet.html#abs-replaced-width"> <del>normal flow, then offset from that position according to these properties).</del><ins>width</ins></a> <ins>and</ins> <a
href="visudet.html#abs-replaced-height"><ins>height</ins></a> <ins>of absolutely
positioned, replaced elements for details.</ins>
</dd>
</dl>
<h2>9.4 <a name="normal-flow">Normal flow</a></h2>
<p>Boxes in the normal flow belong to a <a name="x32"><span class="index-def"
title="formatting context">formatting context</span></a>, which may be
block or inline, but not both simultaneously. <a
href="#block-level"> <del>Block</del><ins>Block-level</ins></a> boxes participate in a <a
href="#block-formatting">block formatting</a> context. <a
href="#inline-level"> <del>Inline</del><ins>Inline-level</ins> boxes</a> participate in an <a
href="#inline-formatting">inline formatting</a> context.
</p>
<h3>9.4.1 <a name="block-formatting">Block formatting <del>context In a</del><ins>contexts</ins></a></h3>
<p><ins>Floats, absolutely positioned elements,</ins> block <del>formatting context, boxes</del><ins>containers (such as
inline-blocks, table-cells, and table-captions) that</ins> are <del>laid out one after the other, vertically, beginning at the top of a containing block. The vertical</del><ins>not block
boxes, and block boxes with 'overflow' other than 'visible'
(except when that value has been propagated to the viewport) establish
new block formatting contexts for their contents.</ins></p>
<p><ins>In a block formatting context, boxes are laid out one after the
other, vertically, beginning at the top of a containing block. The
vertical</ins> distance between two sibling boxes is determined by the <a href="box.html#propdef-margin" class="noxref"><span
class="propinst-margin">'margin'</span></a> properties. Vertical margins
between adjacent <del>block</del><ins>block-level</ins> boxes in a block formatting context <a
href="box.html#collapsing-margins">collapse</a>.
</p>
<p>
In a block formatting context, each box's left outer edge touches the
left edge of the containing block (for right-to-left formatting, right
edges touch). This is true even in the presence of floats (although a
box's <em> <del>content area</del><ins>line boxes</ins></em> may shrink due to the <ins>floats), unless the box
establishes a new block formatting context (in which case the box itself</ins>
<a href="#bfc-next-to-float"><em><ins>may</ins></em> <ins>become narrower</ins></a> <ins>due to
the</ins> floats).
</p>
<p>For information about page breaks in paged media, please consult
the section on <a href="page.html#allowed-page-breaks">allowed
page breaks</a>.
</p>
<h3>9.4.2 <a name="inline-formatting">Inline formatting <del>context</del><ins>contexts</ins></a></h3>
<p>In an inline formatting context, boxes are laid out horizontally,
one after the other, beginning at the top of a containing
block. Horizontal margins, borders, and padding are respected between
these boxes. The boxes may be aligned vertically in different ways: their
bottoms or tops may be aligned, or the baselines of text within them
may be aligned. The rectangular area that contains the boxes that form
a line is called a <span class="index-def" title="line box"><a
name="line-box"><dfn>line box</dfn></a></span>.
</p>
<p>The width of a line box is determined by a <a
href="#containing-block">containing block</a> <del>.</del><ins>and the presence of floats.</ins>
The height of a line
box is determined by the rules given in the section on <a
href="visudet.html#line-height">line height calculations</a>.
</p>
<p>A line box is always tall enough for all of the boxes it contains.
However, it may be taller than the tallest box it contains
(if, for example, boxes are aligned so that baselines line up).
When the height of a box B is less than the height of the line box containing it,
the vertical alignment of B within the line box is determined by
the <a href="visudet.html#propdef-vertical-align" class="noxref"><span class="propinst-vertical-align">'vertical-align'</span></a> property.
When several <del>inline</del><ins>inline-level</ins> boxes cannot fit horizontally within a single
line box, they are distributed among two or more vertically-stacked
line boxes. Thus, a paragraph is a vertical stack of line boxes. Line
boxes are stacked with no vertical separation <ins>(except as specified
elsewhere)</ins> and they never overlap.
</p>
<p>In general, the left edge of a line box touches the left edge
of its containing block and the right edge touches the right edge of
its containing block. However, floating boxes may come between the
containing block edge and the line box edge. Thus, although line
boxes in the same inline formatting context generally have the same
width (that of the containing block), they may vary in width if
available horizontal space is reduced due to <a
href="#floats">floats</a>. Line boxes in the same inline formatting
context generally vary in height (e.g., one line might contain a tall
image while the others contain only text).
</p>
<p>When the total width of the <del>inline</del><ins>inline-level</ins> boxes on a line is less than the
width of the line box containing them, their horizontal distribution
within the line box is determined by the <a href="text.html#propdef-text-align" class="noxref"><span
class="propinst-text-align">'text-align'</span></a> property. If that
property has the value 'justify', the user agent may stretch <del>the</del><ins>spaces
and words in</ins> inline boxes <ins>(but no
5D5A
t inline-table and inline-block
boxes)</ins> as well.
</p>
<p>
<del>Since</del><ins>When</ins> an inline box <del>may not exceed</del><ins>exceeds</ins> the width of a line box, <del>long inline boxes are</del><ins>it is</ins> split into several boxes and these boxes <ins>are</ins> distributed across several line boxes. <ins>If an inline box cannot be split (e.g., if the inline box contains a single character, or language specific word breaking rules disallow a break within the inline box, or if the inline box is affected by a white-space value of nowrap or pre), then the inline box overflows the line box.</ins>
</p>
<p>
When an inline box is split, margins,
borders, and padding have no visual effect where the split <del>occurs. Formatting of margins, borders, and padding may not be fully defined if the split</del>occurs <del>within a bidirectional embedding.</del><ins>(or
at any split, when there are several).</ins>
</p>
<p>Inline boxes may also be split into several boxes <em>within the
same line box</em> due to <a href="#direction">bidirectional text
processing</a>.
</p>
<p id="phantom-line-box"><ins>Line boxes are created as needed to hold
inline-level content within an inline formatting context. Line boxes
that contain no text, no</ins> <a
href="text.html#white-space-prop"><ins>preserved white space,</ins></a> <ins>no inline
elements with non-zero margins, padding, or borders, and no other</ins> <a
href="#positioning-scheme"><ins>in-flow</ins></a> <ins>content (such as images, inline
blocks or inline tables), and do not end with a preserved newline must
be treated as zero-height line boxes for the purposes of determining
the positions of any elements inside of them, and must be treated as
not existing for any other purpose.</ins>
</p>
<div class="html-example"><p>
Here is an example of inline box construction. The following paragraph
(created by the HTML block-level element P) contains anonymous text
interspersed with the elements EM and STRONG:
</p>
<pre><code class="html">
<P>Several <EM>emphasized words</EM> appear
<STRONG>in this</STRONG> sentence, dear.</P>
</code></pre>
<p>The P element generates a block box that contains five inline
boxes, three of which are anonymous:</p>
<ul>
<li>Anonymous: "Several"</li>
<li>EM: "emphasized words"</li>
<li>Anonymous: "appear"</li>
<li>STRONG: "in this"</li>
<li>Anonymous: "sentence, dear."</li>
</ul>
<p>To format the paragraph, the user agent flows the five boxes into
line boxes. In this example, the box generated for the P element
establishes the containing block for the line boxes. If the containing
block is sufficiently wide, all the inline boxes will fit into a
single line box:
</p>
<pre>
Several <em>emphasized words</em> appear <strong>in this</strong> sentence, dear.
</pre>
<p>If not, the inline boxes will be split up and distributed across
several line boxes. The previous paragraph might be split as follows:
</p>
<pre>
Several <em>emphasized words</em> appear
<strong>in this</strong> sentence, dear.
</pre>
or like this:
<pre>
Several <em>emphasized</em>
<em>words</em> appear <strong>in this</strong>
sentence, dear.
</pre>
</div>
<p>In the previous example, the EM box was split into two EM boxes
(call them "split1" and "split2"). Margins, borders,
padding, or text decorations have no visible effect after split1 or
before split2.
</p>
<div class="html-example"><p>
Consider the following example:
</p>
<pre><code class="html">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML <del>4.0//EN"></del><ins>4.01//EN"></ins>
<HTML>
<HEAD>
<TITLE>Example of inline flow on several lines</TITLE>