csswg-drafts/cssom-view/Overview.src.html at ea42350a184f4d991bb93464b8b57e6a587c1606 · w3c/csswg-drafts · GitHub

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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en-US">
 <head>
  <title>CSSOM View Module</title>

  <style type="text/css">
   pre.idl { border:solid thin; background:#eee; color:#000; padding:0.5em }
   pre.idl :link, pre.idl :visited { color:inherit; background:transparent }
   dfn { font-weight:bold; font-style:normal }
   div.example { margin-left:1em; padding-left:1em; border-left:double; color:#222; background:#fcfcfc }
   div.example code { color:inherit }
   p.note {  margin-left:2em; color:green; font-style:italic; font-weight:bold }
   p.note::before { content:"Note: " }
   .XXX { padding:.5em; border:solid red }
   .XXX::before { content:"Issue: " }
   code { color:orangered }
   code :link, code :visited { color:inherit }
  </style>

  <link rel="stylesheet" href="http://www.w3.org/StyleSheets/TR/W3C-[STATUS]">
 </head>

 <body class="draft">
  <div class="head">
   <!--logo-->

   <h1 id="cssom-view-module">CSSOM View Module</h1>

   <h2 class="no-num no-toc" id="w3c-doctype">[LONGSTATUS] [DATE: 3 August 2002]</h2>

   <dl>

    <dt>This Version:</dt>
    <dd class=dontpublish><a href="http://dev.w3.org/csswg/cssom-view/">http://dev.w3.org/csswg/cssom-view/</a></dd>
    <dd class=publish><a href="[VERSION]">[VERSION]</a></dd>

    <dt class=publish>Latest Version:</dt>
    <dd class=publish><a href="[LATEST]">[LATEST]</a></dd>

    <dt class=publish>Latest Editor Draft:</dt>
    <dd class=publish><a href="http://dev.w3.org/csswg/cssom-view/">http://dev.w3.org/csswg/cssom-view/</a></dd>

    <dt>Previous Versions:</dt>
    <dd><a href="http://www.w3.org/TR/2009/WD-cssom-view-20090804/">http://www.w3.org/TR/2009/WD-cssom-view-20090804/</a></dd>
    <dd><a href="http://www.w3.org/TR/2008/WD-cssom-view-20080222/">http://www.w3.org/TR/2008/WD-cssom-view-20080222/</a></dd>

    <dt>Editor:</dt>
    <dd><a href="http://annevankesteren.nl/">Anne van Kesteren</a>
    (<a href="http://www.opera.com/">Opera Software ASA</a>)
    &lt;<a href="mailto:annevk@opera.com">annevk@opera.com</a>&gt;</dd>
   </dl>

   <!-- copyright -->
  </div>

  <hr>

  <h2 id="abstract" class="no-num no-toc">Abstract</h2>

  <p>The APIs introduced by this specification provide authors with a way to
  inspect and manipulate the visual view of a document. This includes
  getting the position of element layout boxes, obtaining the width
  of the viewport through script, and also scrolling an element.</p>


  <h2 id="sotd" class="no-num no-toc">Status of this Document</h2>

  <p><em>This section describes the status of this document at the time of
   its publication. Other documents may supersede this document. A list of
   current W3C publications and the latest revision of this technical report
   can be found in the <a href="http://www.w3.org/TR/">W3C technical reports
   index at http://www.w3.org/TR/.</a></em>

<p>This is the [DATE: 3 August 2002] [LONGSTATUS] of CSSOM View. Please send
comments to
<a href="mailto:www-style@w3.org?subject=%5Bcssom-view%5D%20">www-style@w3.org</a>
(<a href="http://lists.w3.org/Archives/Public/www-style/">archived</a>)
with <samp>[cssom-view]</samp> at the start of the subject line.

  <p>This document was produced by the <a
   href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> (part of
   the <a href="http://www.w3.org/Style/">Style Activity</a>).

  <p>This document was produced by a group operating under the <a
   href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February
   2004 W3C Patent Policy</a>. W3C maintains a <a
   href="http://www.w3.org/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="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
   Claim(s)</a> must disclose the information in accordance with <a
   href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
   6 of the W3C Patent Policy</a>.</p>

  <p>Publication as a Working Draft does not imply endorsement by the W3C
   Membership. This is a draft document and may be updated, replaced or
   obsoleted by other documents at any time. It is inappropriate to cite this
   document as other than work in progress.


  <h2 id="toc" class="no-num no-toc">Table of Contents</h2>

  <!-- toc -->


  <h2 id="background">Background</h2>

  <p>Many of the features defined in this specification have been supported
  by browsers for a long period of time. The goal of this specification is
  to define these features in such a way that they can be implemented by all
  browsers in an interoperable manner. The specification also defines a
  couple of new features that will hopefully be useful to authors. (If they
  are not you can bug us!)</p>


  <h2 id="conformance">Conformance</h2>

<p>All diagrams, examples, and notes in this specification are
non-normative, as are all sections explicitly marked non-normative.
Everything else in this specification is normative.

<p>The key words "MUST", "MUST NOT", "REQUIRED", <!--"SHALL", "SHALL
NOT",--> "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" in the normative parts of this document are to be
interpreted as described in RFC2119. For readability, these words do
not appear in all uppercase letters in this specification. <span
data-anolis-ref>RFC2119</span>

<p>Requirements phrased in the imperative as part of algorithms
(such as "strip any leading space characters" or "return false and
terminate these steps") are to be interpreted with the meaning of the
key word ("must", "should", "may", etc) used in introducing the
algorithm.

<p>Conformance requirements phrased as algorithms or specific steps
may be implemented in any manner, so long as the end result is
equivalent. (In particular, the algorithms defined in this
specification are intended to be easy to follow, and not intended to
be performant.)

<p id="hardwareLimitations">User agents may impose
implementation-specific limits on otherwise unconstrained inputs,
e.g. to prevent denial of service attacks, to guard against running
out of memory, or to work around platform-specific limitations.

<p>When a method or an attribute is said to call another method or attribute, the user agent must invoke its internal API for that attribute or method so that e.g. the author can't change the behavior by overriding attributes or methods with custom properties or functions in ECMAScript.

<p>Unless otherwise stated, string comparisons are done in a <span>case-sensitive</span> manner.

  <p>A conforming user agent implements all the requirements made by this
  specification.</p>


  <h3 id="webidl">Web IDL</h3>

  <p>The IDL fragments in this specification must be
  interpreted as required for conforming IDL fragments, as described in the
  Web IDL specification. <span data-anolis-ref>WEBIDL</span>


  <h2 id="terminology">Terminology</h2>

  <p>Terminology used in this specification is from
  DOM Core,
  DOM Range,
  CSSOM and
  HTML.
  <span data-anolis-ref>DOMCORE</span>
  <span data-anolis-ref>DOMRANGE</span>
  <span data-anolis-ref>CSSOM</span>
  <span data-anolis-ref>HTML</span>

  <p class=XXX><dfn><code>MouseEvent</code></dfn> is defined in &hellip;

  <p><dfn>The HTML <code>body</code> element</dfn> is the first
  <code>body</code>
  <span data-anolis-spec=html title="HTML elements">HTML element</span> child of the root
  <span data-anolis-spec=html title="HTML elements">HTML element</span> <code>html</code>.</p>

  <p><dfn id="content-edge">Content edge</dfn>,
  <dfn id="padding-edge">padding edge</dfn>,
  <dfn id="border-edge">border edge</dfn>, and
  <dfn id="canvas">canvas</dfn> are defined by CSS.
  <!--<span data-anolis-ref>CSS</span>-->

  <p><dfn id="viewport">Viewport</dfn> and
  <dfn id="initial-containing-block">initial containing block</dfn> are
  defined by CSS 2.1 unless there is an ancestor <code>foreignObject</code>
  element in the <code>http://www.w3.org/2000/svg</code> namespace in which
  case that element acts as viewport and initial containing block.
  <!--<span data-anolis-ref>CSS</span>-->

  <p>The term <dfn>content</dfn> refers to the dimensions of the element's
  content area, including overflown content.
  <!--<span data-anolis-ref>CSS</span>-->

  <p>The term <dfn>document content</dfn> refers to the area on the
  <span>canvas</span> that is rendered upon, excluding content on negative
  axis.</p>


  <h3>CSS pixels</h3>

  <p>All coordinates and dimensions for the APIs defined in this
  specification are in CSS pixels. <!--<span data-anolis-ref>CSS</span>-->

  <p class="note">This does not apply to e.g.
  <code title=dom-Window-matchMedia>matchMedia()</code> as the units
  are explicitly given there.</p>


  <h2 id="extensions-to-the-window-interface">Extensions to the <code title>Window</code> Interface</h2>

  <pre class="idl">partial interface <span data-anolis-spec=html>Window</span> {
  <span>MediaQueryList</span> <span title=dom-Window-matchMedia>matchMedia</span>(DOMString <var title>media_query_list</var>);
  readonly attribute <span>Screen</span> <span title=dom-Window-screen>screen</span>;

  // viewport
  readonly attribute long <span title=dom-Window-innerWidth>innerWidth</span>;
  readonly attribute long <span title=dom-Window-innerHeight>innerHeight</span>;

  // viewport scrolling
  readonly attribute long <span title="dom-Window-scrollX">scrollX</span>;
  readonly attribute long <span title="dom-Window-pageXOffset">pageXOffset</span>;
  readonly attribute long <span title="dom-Window-scrollY">scrollY</span>;
  readonly attribute long <span title="dom-Window-pageYOffset">pageYOffset</span>;
  void <span title=dom-Window-scroll>scroll</span>(long <var title>x</var>, long <var title>y</var>);
  void <span title=dom-Window-scrollto>scrollTo</span>(long <var title>x</var>, long <var title>y</var>);
  void <span title="dom-Window-scrollby">scrollBy</span>(long <var title>x</var>, long <var title>y</var>);

  // client
  readonly attribute long <span title=dom-Window-screenX>screenX</span>;
  readonly attribute long <span title=dom-Window-screenY>screenY</span>;
  readonly attribute long <span title=dom-Window-outerWidth>outerWidth</span>;
  readonly attribute long <span title=dom-Window-outerHeight>outerHeight</span>;
};</pre>


  <p>When the
  <dfn title="dom-Window-matchMedia"><code>matchMedia(<var title>media_query_list</var>)</code></dfn>
  method is invoked these steps must be run:</p>

  <ol>
   <li><p>Let <var title>parsed_media_query_list</var> be the result of
   <span title="parse a media query list" data-anolis-spec=cssom>parsing</span>
   <var title>media_query_list</var>.</p></li>

   <li><p>Return a <em>new</em> <code>MediaQueryList</code> object,
   associated with the <code data-anolis-spec=html>Window</code> object, with
   <var title>parsed_media_query_list</var> as its associated
   media query list.</p></li>
  </ol>

  <p>The
  <dfn title=dom-Window-screen><code>screen</code></dfn>
  attribute must return the <code>Screen</code> object
  associated with the <code data-anolis-spec=html>Window</code> object. It always returns the same
  object.</p>

  <p class="note">Accessing <code title="dom-Window-screen">screen</code> through a <code data-anolis-spec=html>WindowProxy</code> object might yield different results
  when the <code data-anolis-spec=domcore>Document</code> is navigated.</p>


  <p>The <dfn title=dom-Window-innerWidth><code>innerWidth</code></dfn>
  attribute must return the
  <span>viewport</span> width including the size of a rendered scroll bar
  (if any).</p>

  <div class="example">
   <p>The following snippet shows how to obtain the width of the
   viewport:</p>

   <pre><code>var viewportWidth = innerWidth</code></pre>
  </div>

  <p>The <dfn title=dom-Window-innerHeight><code>innerHeight</code></dfn>
  attribute must return the
  <span>viewport</span> height including the size of a rendered scroll bar
  (if any).</p>

  <p>The
  <dfn title=dom-Window-scrollX><code>scrollX</code></dfn> and
  <dfn title=dom-Window-pageXOffset><code>pageXOffset</code></dfn>
  attributes must return the x-coordinate,
  relative to the <span>initial containing block</span> origin, of the left
  of the <span>viewport</span>.</p
D53
>

  <p>The
  <dfn title=dom-Window-scrollY><code>scrollY</code></dfn> and
  <dfn title=dom-Window-pageYOffset><code>pageYOffset</code></dfn>
  attributes must return the y-coordinate,
  relative to the <span>initial containing block</span> origin, of the top
  of the <span>viewport</span>.</p>

  <p>When the
  <dfn title=dom-Window-scroll><code>scroll(<var>x</var>,<var>y</var>)</code></dfn>
  method is invoked these steps must be run:</p>

  <ol>
   <li><p>If either <var title>x</var> or <var title>y</var> is
   infinite or NaN terminate this algorithm.</p></li>

   <li>
    <dl>
     <dt>If <span>document content</span> can have overflow to the right
     <dd><p>Let <var title>x</var> be max(0, min(<var title>x</var>,
     <span>content</span> width - <span>content edge</span>
     width)).</p></dd>

     <dt>If <span>document content</span> can have overflow to the left
     (under right-to-left conditions)
     <dd><p>Let <var title>x</var> be min(0, max(<var title>x</var>,
     <span>content edge</span> width - <span>content</span>
     width)).</p></dd>
    </dl>

   <li><p>Let <var title>y</var> be max(0, min(<var title>y</var>,
   <span>document content</span> height - <span>viewport</span>
   height excluding the size of a rendered scroll bar (if any))).</p></li>

   <li><p>Align the x-coordinate <var title>x</var> of the
   <span>document content</span> with the left of the <span>viewport</span>
   and align the y-coordinate <var title>y</var> of the <span>document
   content</span> with the top of the <span>viewport</span>.</p></li>

   <li><p>If the aligning caused content to move <span data-anolis-spec=html>queue a task</span>
   to
   <span data-anolis-spec=domcore title=concept-event-fire>fire an event</span>
   named <code title="event-scroll">scroll</code> that bubbles at the
   <code data-anolis-spec=domcore>Document</code> object, unless a
   <span data-anolis-spec=html title=concept-task>task</span> to fire that event at the <code data-anolis-spec=domcore>Document</code> object
   was already <span data-anolis-spec=html title="queue a task">queued</span>.</p></li>
  </ol>

  <p>When the
  <dfn title=dom-Window-scrollto><code>scrollTo(<var title>x</var>,<var title>y</var>)</code></dfn>
  method is invoked, the user agent must act as if the
  <code title=dom-Window-scroll>scroll()</code> method was invoked with
  the same arguments.</p>

  <p>When the
  <dfn title=dom-Window-scrollby><code>scrollBy(<var title>x</var>,<var title>y</var>)</code></dfn>
  method is invoked, the user agent must act as if the
  <code title=dom-Window-scroll>scroll()</code> method was invoked with
  <var title>x</var> plus <code title="dom-Window-scrollX">scrollX</code>
  as first argument and <var title>y</var> plus
  <code title="dom-Window-scrollY">scrollY</code> as second argument.</p>

  <p>The <dfn title="dom-Window-screenX"><code>screenX</code></dfn>
  attribute must return the x-coordinate,
  relative to the origin of the screen of the output device, of the top of
  the client window as number of pixels, or zero if there is no such
  thing.</p>

  <p>The <dfn title=dom-Window-screenY><code>screenY</code></dfn>
  attribute must return the y-coordinate,
  relative to the origin of the screen of the output device, of the left of
  the client window as number of pixels, or zero if there is no such
  thing.</p>

  <p>The <dfn title=dom-Window-outerWidth><code>outerWidth</code></dfn>
  attribute must return the width of the
  client window. If there is no client window this
  attribute must return zero.</p>

  <p>The <dfn title=dom-Window-outerHeight><code>outerHeight</code></dfn>
  attribute must return the height of the
  client window. If there is no client window
  this attribute must return zero.</p>


  <h3 id="the-mediaquerylist-interface">The <code title>MediaQueryList</code> Interface</h3>

  <p>A <code>MediaQueryList</code> object has an associated media query list
  set on creation and an associated
  <dfn>list of media query list listeners</dfn>, which is initially
  empty.</p>

  <p>If the associated media query list changes in evaluation then, for each
  listener in the <span>list of media query list listeners</span> &mdash; in
  appending order, <span data-anolis-spec=html>queue a task</span> that invokes the listener,
  passing as argument the <code>MediaQueryList</code> object.</p>

  <div class="example">
   <p>A simple piece of code that detects changes in the orientation of the
   viewport can be written as follows:</p>
   <pre><code>function handleOrientationChange(mql) {
  if(mql.matches) // landscape
    &hellip;
  else
    &hellip;
}
var mql = matchMedia("(orientation:landscape)")
mql.addListener(handleOrientationChange)</code></pre>
  </div>

  <pre class="idl">interface <dfn id="mediaquerylist">MediaQueryList</dfn> {
  readonly attribute DOMString <span title="dom-MediaQueryList-media">media</span>;
  readonly attribute boolean <span title="dom-MediaQueryList-matches">matches</span>;
  void <span title="dom-MediaQueryList-addListener">addListener</span>(<span>MediaQueryListListener</span> <var title>listener</var>);
  void <span title="dom-MediaQueryList-removeListener">removeListener</span>(<span>MediaQueryListListener</span> <var title>listener</var>);
};

[Callback, NoInterfaceObject]
interface <dfn id="mediaquerylistlistener">MediaQueryListListener</dfn> {
  void <span>handleChange</span>(<span>MediaQueryList</span> <var title>mql</var>);
};</pre>

  <p>The
  <dfn title="dom-MediaQueryList-media"><code>media</code></dfn>
  must return the
  <span title="serialize a media query list" data-anolis-spec=cssom>serialized</span> form of the associated media query list.</p>

  <p>The <dfn title="dom-MediaQueryList-matches"><code>matches</code></dfn>
  matches the state of the rendered <code data-anolis-spec=domcore>Document</code> and false if it
  does not.</p>

  <p>When the
  <dfn title="dom-MediaQueryList-addListener"><code>addListener(<var>listener</var>)</code></dfn>
  is invoked <var title>listener</var> must be
  appended to the <span>list of media query list listeners</span>, unless
  it is already in the <span>list of media query list listeners</span>.</p>

  <p>When the
  <dfn title="dom-MediaQueryList-removeListener"><code>removeListener(<var>listener</var>)</code></dfn>
  is invoked <var title>listener</var> must be
  removed from the <span>list of media query list listeners</span>.</p>


  <h3 id="the-screen-interface">The <code title>Screen</code> Interface</h3>

  <p>As its name suggests, the <code>Screen</code> interface represents
  information about the screen of the output device.</p>

  <pre class="idl">interface <dfn id="screen">Screen</dfn> {
  readonly attribute unsigned long <span title=dom-Screen-availWidth>availWidth</span>;
  readonly attribute unsigned long <span title=dom-Screen-availHeight>availHeight</span>;
  readonly attribute unsigned long <span title=dom-Screen-width>width</span>;
  readonly attribute unsigned long <span title=dom-Screen-height>height</span>;
  readonly attribute unsigned long <span title=dom-Screen-colorDepth>colorDepth</span>;
  readonly attribute unsigned long <span title=dom-Screen-pixelDepth>pixelDepth</span>;
};</pre>

  <p>The <dfn title=dom-Screen-availWidth><code>availWidth</code></dfn>
  attribute must return the available width of the
  rendering surface of the output device.</p>

  <p>The <dfn title=dom-Screen-availHeight><code>availHeight</code></dfn>
  attribute must return the available height of the
  rendering surface of the output device.</p>

  <p>The <dfn title=dom-Screen-width><code>width</code></dfn> attribute
  must return the width of the output device.</p>

  <p>The <dfn title=dom-Screen-height><code>height</code></dfn> attribute
  must return the height of the output device.</p>

  <p>The <dfn title=dom-Screen-colorDepth><code>colorDepth</code></dfn> and
  <dfn title=dom-Screen-pixelDepth><code>pixelDepth</code></dfn> attributes
  must both return the number of bits allocated to
  colors (i.e. excluding the alpha channel) in the output device. If the
  output device does not support colors these attributes
  must return zero.</p>
  <!-- pixelDepth is not supported by Internet Explorer 7 -->


  <h2 id="extensions-to-the-document-interface">Extensions to the <code title>Document</code> Interface</h2>

  <pre class="idl">partial interface <span data-anolis-spec=domcore>Document</span> {
  <span data-anolis-spec=domcore>Element</span>? <span title=dom-Document-elementFromPoint>elementFromPoint</span>(float <var title>x</var>, float <var title>y</var>);
  <span>CaretPosition</span>? <span title=dom-Document-caretPositionFromPoint>caretPositionFromPoint</span>(float <var title>x</var>, float <var title>y</var>);
};</pre>

  <p>The
  <dfn title=dom-Document-elementFromPoint><code>elementFromPoint(<var>x</var>, <var>y</var>)</code></dfn>
  method must return the element at coordinates <var>x</var>,<var>y</var> in
  the <span>viewport</span>. The element to be returned is determined
  through hit testing. If either argument is negative, <var title>x</var> is
  greater than the <span>viewport</span> width excluding the size of a
  rendered scroll bar (if any), or <var title>y</var> is greater than the
  <span>viewport</span> height excluding the size of a rendered scroll bar
  (if any), the method must return null. If there is no element at the given
  position the method must return the root element, if any, or null
  otherwise.</p>

  <p>The
  <dfn title=dom-Document-caretPositionFromPoint><code>caretPositionFromPoint(<var>x</var>, <var>y</var>)</code></dfn>
  method must return the result of running these steps:</p>

  <ol>
   <li><p>If either argument is negative, <var title>x</var> is greater
   than the <span>viewport</span> width excluding the size of a rendered
   scroll bar (if any), <var title>y</var> is greather than the
   <span>viewport</span> height excluding the size of a rendered scroll bar
   (if any) return null.</p></li>

   <li><p>If at the coordinates <var title>x</var>,<var title>y</var>
   in the <span>viewport</span> no text insertion point indicator would have
   been inserted return null.</p></li>

   <li>
    <p>If at the coordinates <var title>x</var>,<var title>y</var>
    in the <span>viewport</span> a text insertion point indicator would have
    been inserted in a text entry widget which is also a replaced element
    return a <span>caret position</span> with its properties set as
    follows:</p>

    <dl>
     <dt><span>caret node</span></dt>
     <dd><p>The node corresponding to the text entry widget.</p></dd>

     <dt><span>caret offset</span></dt>
     <dd><p>The amount of 16-bit units to the left of where the
     text insertion point indicator would have inserted.</p></dd>

     <dt><span>caret range</span></dt>
     <dd><p>null</p></dd>
    </dl>
   </li>

   <li>
    <p>Otherwise, return a <span>caret position</span> where the
    <span>caret range</span> is a collapsed
    <code data-anolis-spec=domrange>Range</code> object for the position
    where the text insertion point indicator would have been inserted and
    the other properties are set as follows:</p>

    <dl>
     <dt><span>caret node</span></dt>
     <dd><p>The <code data-anolis-spec=domrange title=dom-Range-startContainer>startContainer</code>
     of the <span>caret range</span>.</p></dd>

     <dt><span>caret offset</span></dt>
     <dd><p>The <code data-anolis-spec=domrange title=dom-Range-startOffset>startOffset</code> of
     the <span>caret range</span>.</p>
    </dl>
   </li>
  </ol>

  <p class="note">The specifics of hit testing are out of scope of this
  specification and therefore the exact details of
  <code title=dom-Document-elementFromPoint>elementFromPoint()</code> and
  <code title=dom-Document-caretPositionFromPoint>caretPositionFromPoint()</code>
  are therefore too. Hit testing will hopefully be defined in a future
  revision of CSS or HTML.</p>


  <h3 id=the-caretposition-interface>The <code title>CaretPosition</code> Interface</h3>

  <p>A <dfn>caret position</dfn> gives the position of a
  text insertion point indicator. It always has an associated
  <dfn>caret node</dfn>, <dfn>caret offset</dfn>, and
  <dfn>caret range</dfn>. It is represented by a <code>CaretPosition</code>
  object.</p>

  <pre class="idl">interface <dfn id="caretposition">CaretPosition</dfn> {
  readonly attribute <span data-anolis-spec=domcore>Node</span> <span title=dom-CaretPosition-offsetNode>offsetNode</span>;
  readonly attribute unsigned long <span title=dom-CaretPosition-offset>offset</span>;<!--
  readonly attribute <span data-anolis-spec=domrange>Range</span>? <span title="dom-CaretPosition-range">range</span>;-->
};</pre>

  <p>The
  <dfn title=dom-CaretPosition-offsetNode><code>offsetNode</code></dfn>
  attribute must return the <span>caret node</span>.</p>

  <p>The
  <dfn title=dom-CaretPosition-offset><code>offset</code></dfn>
  attribute must return the <span>caret offset</span>.</p>

  <!--
  <p>The
  <dfn id="dom-caretposition-range" title="dom-CaretPosition-range"><code>range</code></dfn>
  attribute must return the <span>caret range</span>.</p>
  -->
  <!-- https://bugs.webkit.org/show_bug.cgi?id=27046 -->


  <h2 id="extensions-to-the-element-interface">Extensions to the <code title>Element</code> Interface</h2>

  <pre class="idl">partial interface <span data-anolis-spec=domcore>Element</span> {
  <span>ClientRectList</span> <span title=dom-Element-getClientRects>getClientRects</span>();
  <span>ClientRect</span> <span title=dom-Element-getBoundingClientRect>getBoundingClientRect</span>();

  // scrolling
  void <span title=dom-Element-scrollIntoView>scrollIntoView</span>(optional boolean <var title>top</var>);
           attribute long <span title=dom-Element-scrollTop>scrollTop</span>;   // scroll on setting
           attribute long <span title=dom-Element-scrollLeft>scrollLeft</span>;  // scroll on setting
  readonly attribute long <span title=dom-Element-scrollWidth>scrollWidth</span>;
  readonly attribute long <span title=dom-Element-scrollHeight>scrollHeight</span>;

  readonly attribute long <span title=dom-Element-clientTop>clientTop</span>;
  readonly attribute long <span title=dom-Element-clientLeft>clientLeft</span>;
  readonly attribute long <span title=dom-Element-clientWidth>clientWidth</span>;
  readonly attribute long <span title=dom-Element-clientHeight>clientHeight</span>;
};</pre>


  <h3>The <code title>getClientRects()</code> and
  <code title>getBoundingClientRect()</code> methods</h3>

  <p>The <code title=dom-Element-getClientRects>getClientRects()</code> and <code title=dom-Element-getBoundingClientRect>getBoundingClientRect()</code>
  methods provide information about the position of the border box edges of
  an element relative to the viewport. The objects these methods return
  must be static. That is, changes to the underlying
  document are not reflected in the objects.</p>

  <p>The
  <dfn title=dom-Element-getClientRects><code>getClientRects()</code></dfn>
  method, when invoked, must return the result of the
  following algorithm:</p>

  <ol>
   <li><p>If the element on which it was invoked does not have an associated
   CSS layout box and is not in the <code>http://www.w3.org/2000/svg</code>
   namespace return an empty <code>ClientRectList</code> object and stop
   this algorithm.</p></li>

   <li><p>If the element does not have an associated CSS layout box and is
   in the <code>http://www.w3.org/2000/svg</code> namespace return a
   <code>ClientRectList</code> object containing a single
   <code>ClientRect</code> object that describes the bounding box of the
   element as defined by the SVG specification.
   <span data-anolis-ref>SVG</span>

   <li>
    <p>Return a <code>ClientRectList</code> object containing a list of
    <code>ClientRect</code> objects in content order describing the border
    boxes (including those with a height or width of zero) with the
    following constraints:</p>

    <ul>
     <li><p>If the element on which the method was invoked has a computed
     value for <code>display</code> property of <code>table</code> or
     <code>inline-table</code> include both the table box and the caption
     box, if any, but not the anonymous container box.
     <!--<span data-anolis-ref>CSS</span>-->

     <li><p>Replace each
     <a href="http://www.w3.org/TR/CSS21/visuren.html#anonymous-block-level">anonymous
     block box</a> with its child box(es) and repeat this until no anonymous
     block boxes are left in the final list.
     <!--<span data-anolis-ref>CSS</span>-->
    </ul>
   </li>
  </ol>

  <p>The
  <dfn title=dom-Element-getBoundingClientRect><code>getBoundingClientRect()</code></dfn>
  method, when invoked, must return the result of the
  following algorithm:</p>

  <ol>
   <li><p>Let <var>list</var> be the result of invoking
   <code title=dom-Element-getClientRects>getClientRects()</code> on the
   same element this method was invoked on.</p></li>

   <li><p>If the <var>list</var> is empty return a <code>ClientRect</code>
   object whose <code title=dom-ClientRect-top>top</code>,
   <code title=dom-ClientRect-right>right</code>,
   <code title=dom-ClientRect-bottom>bottom</code> and
   <code title=dom-ClientRect-left>left</code> members are zero.</p></li>

   <li><p>Otherwise, return a <code>ClientRect</code> object describing the
   smallest rectangle that includes the first rectangle in <var>list</var>
   and all of the remaining rectangles of which the height or width is not
   zero.</p></li>
  </ol>

  <div class="example">
   <p>The following snippet gets the dimensions of the first
   <code>div</code> element in a document:</p>

   <pre><code>var example = document.getElementsByTagName("div")[0].getBoundingClientRect();
var exampleWidth = example.width;
var exampleHeight = example.height;</code></pre>
  </div>


  <h3><code title>Element</code> Scrolling Members</h3>

  <p>To <dfn>scroll an element into view</dfn>, optionally with an
  <i title>align to top flag</i> set, means to run these steps for each
  ancestor element or <span>viewport</span> that establishes a
  scrolling box, in order of innermost to outermost scrolling box:</p>

  <ol>
   <li><p>If the <code data-anolis-spec=domcore>Document</code> associated
   with the element to be
   scrolled into view is not <span data-anolis-spec=html>same origin</span> with the
   <code data-anolis-spec=domcore>Document</code> associated with the element or
   <span>viewport</span> associated with the scrolling box, terminate these
   steps.</p></li>

   <li><p>If the <i title>align to top flag</i> is set align the top of
   the border box of the element to be scrolled into view with the top of
   the scrolling box.</p></li>

   <li><p>Otherwise, if the <i title>align to top flag</i> is not set
   align the bottom of the border box of the element to be scrolled into
   view with the bottom of the scrolling box.</p></li>

   <li><p>Align the left of the border box of the element to be scrolled
   into view with the left of the scrolling box.</p</li>
   <!-- RTL is not special cased in implementations?! -->

   <li><p>If the aligning did not cause content to move terminate these
   steps.</p></li>

   <li>
    <dl>
     <dt>If the scrolling box is associated with an element</dt>
     <dd><p><span data-anolis-spec=html>Queue a task</span> to <span data-anolis-spec=domcore title=concept-event-fire>fire an event</span>
     named <code title="event-scroll">scroll</code> at the element
     associated with the scrolling box, unless a <span data-anolis-spec=html title=concept-task>task</span> to fire
     that event at that element was already
     <span data-anolis-spec=html title="queue a task">queued</span>.</p></dd>

     <dt>If the scrolling box is associated with a <span>viewport</span></dt>
     <dd><p><span data-anolis-spec=html>Queue a task</span> to <span data-anolis-spec=domcore title=concept-event-fire>fire an event</span>
     named <code title="event-scroll">scroll</code> that bubbles at the
     <code data-anolis-spec=domcore>Document</code> object associated with the <span>viewport</span>,
     unless a <span data-anolis-spec=html title=concept-task>task</span> to fire that event at that
     <code data-anolis-spec=domcore>Document</code> object was already
     <span data-anolis-spec=html title="queue a task">queued</span>.</p></dd>
    </dl>
   </li>
  </ol>


  <p>To <dfn>scroll an element</dfn> to <var title>x</var>,<var title>y</var> means to:</p>

  <ol>
   <li><p>If either <var title>x</var> or <var title>y</var> is
   infinite or NaN terminate this algorithm.</p>

   <li>
    <dl>
     <dt>If the element can have overflow to the right</dt>

     <dd><p>Let <var title>x</var> be max(0, min(<var title>x</var>,
     <span>content</span> width -
     <span>content edge</span> width)).</p></dd>

     <dt>If the element can have overflow to the left (under right-to-left
     conditions)</dt>

     <dd><p>Let <var title>x</var> be min(0, max(<var title>x</var>,
     <span>content edge</span> width -
     <span>content</span> width)).</p></dd>
    </dl>
   </li>

   <li><p>Let <var title>y</var> be max(0, min(<var title>y</var>,
   <span>content</span> height - <span>content edge</span> height)).</p></li>

   <li><p>Align <span>content</span> x-coordinate <var title>x</var> with
   the left of the <span>content edge</span> of the element and align
   <span>content</span> y-coordinate <var title>y</var> with
   the top of the <span>content edge</span> of the element.</p></li>

   <li><p>If the aligning caused content to move <span data-anolis-spec=html>queue a task</span>
   to <span data-anolis-spec=domcore title=concept-event-fire>fire an event</span> named
   <code title="event-scroll">scroll</code> at the element, unless a
   <span data-anolis-spec=html title=concept-task>task</span> to fire that event at that element was already
   <span  data-anolis-spec=html title="queue a task">queued</span>.</p></li>
  </ol>


  <p>The
  <dfn title=dom-Element-scrollIntoView><code>scrollIntoView([<var>top</var>])</code></dfn>
  method must run these steps:</p>

  <ol>
   <li><p>If the element does not have any associated CSS layout box
   terminate these steps.</p></li>

   <li><p><span title="scroll an element into view">Scroll the element into view</span>
   with the <i title>align to top flag</i> set if <var title>top</var>
   is true or omitted.</p></li>
  </ol>


  <p>The <dfn title=dom-Element-scrollTop><code>scrollTop</code></dfn>
  attribute must return the result of running these
  steps:</p>

  <ol>
   <li><p>If the element does not have any associated CSS layout box or the
   element is the root element and the <code data-anolis-spec=domcore>Document</code> is in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span> return zero and terminate these steps.</p></li>

   <li><p>If the element is the root element return the value of
   <code title="dom-Window-scrollY">scrollY</code>.</p></li>

   <li><p>If the element is <span>the HTML <code>body</code> element</span>,
   the <code data-anolis-spec=domcore>Document</code> is in <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>, and the element
   does not have any overflow, return the value of
   <code title=dom-Window-scrollY>scrollY</code>.</p></li>

   <li><p>Return the y-coordinate of the <span>content</span> at the
   alignment point with the top of the <span>content edge</span> of the
   element.</p></li>
  </ol>

  
E8EB
<p>When setting the <code title=dom-Element-scrollTop>scrollTop</code>
  attribute these steps must be run:</p>

  <ol>
   <li><p>Let <var title>y</var> be the given value.</p></li>

   <li><p>If the element does not have any associated CSS layout box, the
   element is the root element and the <code data-anolis-spec=domcore>Document</code> is in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>, or the element has no overflow, terminate these
   steps.</p></li>

   <li><p>If the element is the root element invoke
   <code title=dom-Window-scroll>scroll()</code> with zero as first
   argument and <var title>y</var> as second.</p></li>

   <li><p>If the element is <span>the HTML <code>body</code> element</span>,
   the <code data-anolis-spec=domcore>Document</code> is in <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>, and the element
   does not have any vertical overflow, invoke
   <code title=dom-Window-scroll>scroll()</code> with
   <code title=dom-Window-scrollX>scrollX</code> as first
   argument and <var title>y</var> as second.</p></li>

   <li><p><span title="scroll an element">Scroll the element</span> to
   <code title=dom-Element-scrollLeft>scrollLeft</code>,<var title>y</var>.
  </ol>

  <p>The <dfn title=dom-Element-scrollLeft><code>scrollLeft</code></dfn>
  attribute must return the result of running these
  steps:</p>

  <ol>
   <li><p>If the element does not have any associated CSS layout box or the
   element is the root element and the <code data-anolis-spec=domcore>Document</code> is in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span> return zero and terminate these steps.</p></li>

   <li><p>If the element is the root element return the value of
   <code title=dom-Window-scrollX>scrollX</code>.</p></li>

   <li><p>If the element is <span>the HTML <code>body</code> element</span>,
   the <code data-anolis-spec=domcore>Document</code> is in <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>, and the element
   does not have any overflow, return the value of
   <code title=dom-Window-scrollX>scrollX</code>.</p></li>

   <li><p>Return the x-coordinate of the <span>content</span> at the
   alignment point with the left of the <span>content edge</span> of the
   element.</p></li>
  </ol>

  <p>When setting the <code title=dom-Element-scrollLeft>scrollLeft</code> attribute these steps
  must be run:</p>

  <ol>
   <li><p>Let <var title>x</var> be the given value.</p></li>

   <li><p>If the element does not have any associated CSS layout box, the
   element is the root element and the <code data-anolis-spec=domcore>Document</code> is in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>, or the element has no overflow, terminate these
   steps.</p></li>

   <li><p>If the element is the root element invoke
   <code title=dom-Window-scroll>scroll()</code> with
   <var title>x</var> as first argument and zero as second.</p></li>

   <li><p>If the element is <span>the HTML <code>body</code> element</span>,
   the <code data-anolis-spec=domcore>Document</code> is in <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>, and the element
   does not have any vertical overflow, invoke
   <code title="dom-Window-scroll">scroll()</code> with
   <var title>x</var> as first argument and
   <code title=dom-Window-scrollY>scrollY</code> as second.</p></li>

   <li><p><span title="Scroll an element">Scroll the element</span> to
   <var title>x</var>,<code title=dom-Element-scrollTop>scrollTop</code>.
  </ol>

  <p>The <dfn title=dom-Element-scrollWidth><code>scrollWidth</code></dfn>
  attribute must return the result of running these
  steps:</p>

  <ol>
   <li><p>If the element does not have any associated CSS layout box return
   zero and terminate these steps.</p></li>

   <li><p>If the element is the root element and the
   <code data-anolis-spec=domcore>Document</code> is not in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>
   return
   max(<span>document content</span> width, value of <code title=dom-Window-innerWidth>innerWidth</code>).</p></li>

   <li><p>If the element is <span>the HTML <code>body</code> element</span>
   and the <code data-anolis-spec=domcore>Document</code> is in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>
   return
   max(<span>document content</span> width, value of <code title=dom-Window-innerWidth>innerWidth</code>).</p></li>

   <li><p>Return the computed value of the '<code>padding-left</code>'
   property, plus the computed value of the '<code>padding-right</code>',
   plus the <span>content</span> width of the element.</p></li>
  </ol>

  <p>The <dfn title=dom-Element-scrollHeight><code>scrollHeight</code></dfn>
  attribute must return the result of running these
  steps:</p>

  <ol>
   <li><p>If the element does not have any associated CSS layout box return
   zero and terminate these steps.</p></li>

   <li><p>If the element is the root element and the
   <code data-anolis-spec=domcore>Document</code> is not in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>
   return
   max(<span>document content</span> height, value of <code title=dom-Window-innerHeight>innerHeight</code>).</p></li>

   <li><p>If the element is <span>the HTML <code>body</code> element</span>
   and the <code data-anolis-spec=domcore>Document</code> is in
   <span data-anolis-spec=domcore title=concept-quirks-mode>quirks mode</span>
   return
   max(<span>document content</span> height, value of <code title=dom-Window-innerHeight>innerHeight</code>).</p></li>

   <li><p>Return the computed value of the '<code>padding-top</code>'
   property, plus the computed value of the '<code>padding-bottom</code>',
   plus the <span>content</span> height of the element.</p></li>
  </ol>

  <!-- for inline boxes offsetWidth and offsetHeight are identical to offset* -->


  <h3 id="client-attributes">The <code title>clientTop</code>,
  <code title>clientLeft</code>, <code title>clientWidth</code>, and
  <code title>clientHeight</code> attributes</h3>

  <p>The <dfn title=dom-Element-clientTop><code>clientTop</code></dfn>,
  <dfn title=dom-Element-clientLeft><code>clientLeft</code></dfn>,
  <dfn title=dom-Element-clientWidth><code>clientWidth</code></dfn>, and
  <dfn title=dom-Element-clientHeight><code>clientHeight</code></dfn>
  attributes must return zero if the element does not
  have any associated CSS layout box or if the CSS layout box is inline.
  Otherwise, these attributes must behave as defined in
  the remainder of this section.</p>

  <p>The <code title=dom-Element-clientTop>clientTop</code> attribute returns the computed value of the
  '<code>border-top-width</code>' property plus the width of any scrollbar
  rendered between the top <span>padding edge</span> and the top
  <span>border edge</span>.</p>

  <p>The <code title=dom-Element-clientLeft>clientLeft</code> attribute returns the computed
  value of the '<code>border-left-width</code>' property plus the width of
  any scrollbar rendered between the left <span>padding edge</span> and the
  left <span>border edge</span>.

  <p>The <code title=dom-Element-clientWidth>clientWidth</code> attribute returns the
  <span>viewport</span> width excluding the size of a rendered scroll bar
  (if any) if the element is the root element and the
  width of the <span>padding edge</span> (excluding the width of any
  rendered scrollbar between the <span>padding edge</span> and the
  <span>border edge</span>) otherwise.</p>

  <p>The <code title=dom-Element-clientHeight>clientHeight</code> attribute returns the
  <span>viewport</span> height excluding the size of a rendered scroll bar
  (if any) if the element is the root element and the
  height of the <span>padding edge</span> (excluding the width of any
  rendered scrollbar between the <span>padding edge</span> and the
  <span>border edge</span>) otherwise.</p>


  <h2 id="extensions-to-the-htmlelement-interface">Extensions to the <code title>HTMLElement</code> Interface</h2>

  <pre class="idl">partial interface <span data-anolis-spec=html>HTMLElement</span> {
  readonly attribute Element <span title=dom-HTMLElement-offsetParent>offsetParent</span>;
  readonly attribute long <span title=dom-HTMLElement-offsetTop>offsetTop</span>;
  readonly attribute long <span title=dom-HTMLElement-offsetLeft>offsetLeft</span>;
  readonly attribute long <span title=dom-HTMLElement-offsetWidth>offsetWidth</span>;
  readonly attribute long <span title=dom-HTMLElement-offsetHeight>offsetHeight</span>;
};</pre>


  <h3 id="offset-attributes">The <code title>offsetParent</code>,
  <code title>offsetTop</code>, <code title>offsetLeft</code>,
  <code title>offsetWidth</code>, and <code title>offsetHeight</code>
  attributes</h3>

  <p>The
  <dfn title=dom-HTMLElement-offsetParent><code>offsetParent</code></dfn>
  attribute must return the result of running these
  steps:</p>

  <ol>