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Revision 356609 of bottom

  • Revision slug: CSS/bottom
  • Revision title: bottom
  • Revision id: 356609
  • Created:
  • Creator: ethertank
  • Is current revision? No
  • Comment id ...etc.

Revision Content

{{CSSRef}}

Summary

The bottom CSS property participates in specifying the position of positioned elements.

For absolutely positioned elements, that is those with position: absolute or position: fixed, it specifies the distance between the bottom margin edge of the element and the bottom edge of its containing block.

For relatively positioned elements, that is those with position: relative, it specifies the distance the element is moved above its normal position.

However, the {{Cssxref("top")}} property overrides the bottom property, so if top is not auto, the computed value of bottom is the negative of the computed value of top.

  • {{Xref_cssinitial}} {{Cssinitial("bottom")}}
  • Applies to positioned elements
  • {{Xref_cssinherited}} no
  • Percentages refer to height of containing block
  • Media {{Xref_cssvisual}}
  • {{Xref_csscomputed}} absolute length, percentage, or auto

Syntax

Formal syntax: {{csssyntax("bottom")}}
bottom: 3px         /* <length> values */
bottom: 2.4em

bottom: 10%         /* <percentages> of the height of the containing block */

bottom: auto

bottom: inherit

Values

<length>
Is a negative, null or positive {{xref_csslength}} that represents:
  • for absolutely positioned elements, the distance to the bottom edge of the containing block;
  • for relatively positioned elements, the offset that the element is moved above its position in the normal flow if it wasn't positioned.
<percentage>
Is a {{xref_csspercentage}} of the containing block's height, used as described in the summary.
auto
Is a keyword that represents:
  • for absolutely positioned elements, the position the element based on the {{Cssxref("top")}} property and treat height: auto as a height based on the content.
  • for relatively positioned elements, the offset the element from its original position based on the {{Cssxref("top")}} property, or if top is also auto, do not offset it at all.
inherit
Is a keyword indicating that the value is the same than the computed value from its parent element (which may not be its containing block). This computed value is then handled like it was a {{xref_csslength}}, {{xref_csspercentage}} or the auto keyword.

Examples

element { 
    position: absolute;
    bottom: 20px; 
    height: 200px;
    border: 1px solid #000;
}

The following sample page contrasts position:absolute and position:fixed. When the regular text becomes taller than the viewable portion of the page (the browser window's viewport), blocks positioned with position:absolute will scroll with the page, while blocks positioned with position:fixed will not.

<!DOCTYPE html>
<html>
<head>
<title>Position at bottom, absolute or fixed</title>
<style type="text/css">
p {font-size:30px; line-height:3em;}
div.pos {width:49%; text-align:center; border:2px solid #00f;}
div#abs {position:absolute; bottom:0; left:0;}
div#fix {position:fixed; bottom:0; right:0;}
</style>
</head>
<body>
  <p>This<br>is<br>some<br>tall,<br>tall,
    <br>tall,<br>tall,<br>tall<br>content.</p>
  <div id="fix" class="pos"><p>Fixed</p></div>
  <div id="abs" class="pos"><p>Absolute</p></div>
</body>
</html>

Specifications

Specification Status Comment
{{SpecName('CSS2.1', 'visuren.html#choose-position', 'bottom')}} {{Spec2('CSS2.1')}}  

Browser compatibility

{{CompatibilityTable}}
Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 1.0 {{CompatGeckoDesktop("1.0")}} 5 6 1.0 (85)
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support {{CompatUnknown}} {{CompatGeckoMobile("1.9.2")}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}}

See also

  • {{CSS_Reference:Position}}

Revision Source

<div>{{CSSRef}}</div>
<h2 id="Summary" name="Summary">Summary</h2>
<p>The <code>bottom</code> <a href="/en-US/docs/CSS" title="CSS">CSS</a> property participates in specifying the position of <em>positioned elements</em>.</p>
<p>For <em>absolutely positioned elements</em>, that is those with <code>position: absolute</code> or <code>position: fixed</code>, it specifies the distance between the bottom margin edge of the element and the bottom edge of its containing block.</p>
<p>For <em>relatively positioned elements</em>, that is those with <code>position: relative</code>, it specifies the distance the element is moved above its normal position.</p>
<p>However, the {{Cssxref("top")}} property overrides the bottom property, so if <code>top</code> is not <code>auto</code>, the computed value of <code>bottom</code> is the negative of the computed value of <code>top</code>.</p>
<ul class="cssprop">
  <li><dfn>{{Xref_cssinitial}}</dfn> {{Cssinitial("bottom")}}</li>
  <li><dfn>Applies to</dfn> <a href="/en-US/docs/CSS/position" title="CSS/position">positioned elements</a></li>
  <li><dfn>{{Xref_cssinherited}}</dfn> no</li>
  <li><dfn>Percentages</dfn> refer to height of containing block</li>
  <li><dfn>Media</dfn> {{Xref_cssvisual}}</li>
  <li><dfn>{{Xref_csscomputed}}</dfn> absolute length, percentage, or auto</li>
</ul>
<h2 id="Syntax" name="Syntax">Syntax</h2>
<pre class="twopartsyntaxbox">
<a href="/en-US/docs/CSS/Value_definition_syntax" title="CSS/Value_definition_syntax">Formal syntax</a>: {{csssyntax("bottom")}}
</pre>
<pre>
bottom: 3px         /* &lt;length&gt; values */
bottom: 2.4em

bottom: 10%         /* &lt;percentages&gt; of the height of the containing block */

bottom: auto

bottom: inherit
</pre>
<h3 id="Values">Values</h3>
<dl>
  <dt><code>&lt;length&gt;</code></dt>
  <dd>Is a negative, null or positive {{xref_csslength}} that represents:
    <ul>
      <li>for <em>absolutely positioned elements</em>, the distance to the bottom edge of the containing block;</li>
      <li>for <em>relatively positioned elements</em>, the offset that the element is moved above its position in the normal flow if it wasn't positioned.</li>
    </ul></dd>
  <dt><code>&lt;percentage&gt;</code></dt>
  <dd>Is a {{xref_csspercentage}} of the containing block's height, used as described in the <a href="#Summary">summary</a>.</dd>
  <dt><code>auto</code></dt>
  <dd>Is a keyword that represents:
    <ul>
      <li>for absolutely positioned elements, the position the element based on the {{Cssxref("top")}} property and treat <code>height: auto</code> as a height based on the content.</li>
      <li>for relatively positioned elements, the offset the element from its original position based on the {{Cssxref("top")}} property, or if <code>top</code> is also <code>auto</code>, do not offset it at all.</li>
    </ul></dd>
  <dt><code>inherit</code></dt>
  <dd>Is a keyword indicating that the value is the same than the computed value from its parent element (which may not be its containing block). This computed value is then handled like it was a {{xref_csslength}}, {{xref_csspercentage}} or the <code>auto</code> keyword.</dd>
</dl>
<h2 id="Examples" name="Examples">Examples</h2>
<pre class="brush: css; highlight:[2]">
element { 
    position: absolute;
    bottom: 20px; 
    height: 200px;
    border: 1px solid #000;
}
</pre>
<p>The following sample page contrasts <code>position:absolute</code> and <code>position:fixed</code>. When the regular text becomes taller than the viewable portion of the page (the browser window's viewport), blocks positioned with <code>position:absolute</code> will scroll with the page, while blocks positioned with <code>position:fixed</code> will not.</p>
<pre class="brush: html">
&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt;
&lt;title&gt;Position at bottom, absolute or fixed&lt;/title&gt;
&lt;style type="text/css"&gt;
p {font-size:30px; line-height:3em;}
div.pos {width:49%; text-align:center; border:2px solid #00f;}
div#abs {position:absolute; bottom:0; left:0;}
div#fix {position:fixed; bottom:0; right:0;}
&lt;/style&gt;
&lt;/head&gt;
&lt;body&gt;
  &lt;p&gt;This&lt;br&gt;is&lt;br&gt;some&lt;br&gt;tall,&lt;br&gt;tall,
    &lt;br&gt;tall,&lt;br&gt;tall,&lt;br&gt;tall&lt;br&gt;content.&lt;/p&gt;
  &lt;div id="fix" class="pos"&gt;&lt;p&gt;Fixed&lt;/p&gt;&lt;/div&gt;
  &lt;div id="abs" class="pos"&gt;&lt;p&gt;Absolute&lt;/p&gt;&lt;/div&gt;
&lt;/body&gt;
&lt;/html&gt;
</pre>
<h2 id="Specifications" name="Specifications">Specifications</h2>
<table class="standard-table">
  <thead>
    <tr>
      <th scope="col">Specification</th>
      <th scope="col">Status</th>
      <th scope="col">Comment</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>{{SpecName('CSS2.1', 'visuren.html#choose-position', 'bottom')}}</td>
      <td>{{Spec2('CSS2.1')}}</td>
      <td>&nbsp;</td>
    </tr>
  </tbody>
</table>
<h2 id="Browser_compatibility" name="Browser_compatibility">Browser compatibility</h2>
<div>{{CompatibilityTable}}</div>
<div id="compat-desktop">
  <table class="compat-table">
    <tbody>
      <tr>
        <th>Feature</th>
        <th>Chrome</th>
        <th>Firefox (Gecko)</th>
        <th>Internet Explorer</th>
        <th>Opera</th>
        <th>Safari (WebKit)</th>
      </tr>
      <tr>
        <td>Basic support</td>
        <td>1.0</td>
        <td>{{CompatGeckoDesktop("1.0")}}</td>
        <td>5</td>
        <td>6</td>
        <td>1.0 (85)</td>
      </tr>
    </tbody>
  </table>
</div>
<div id="compat-mobile">
  <table class="compat-table">
    <tbody>
      <tr>
        <th>Feature</th>
        <th>Android</th>
        <th>Firefox Mobile (Gecko)</th>
        <th>IE Phone</th>
        <th>Opera Mobile</th>
        <th>Safari Mobile</th>
      </tr>
      <tr>
        <td>Basic support</td>
        <td>{{CompatUnknown}}</td>
        <td>{{CompatGeckoMobile("1.9.2")}}</td>
        <td>{{CompatUnknown}}</td>
        <td>{{CompatUnknown}}</td>
        <td>{{CompatUnknown}}</td>
      </tr>
    </tbody>
  </table>
</div>
<h2 id="See_also">See also</h2>
<ul>
  <li>{{CSS_Reference:Position}}</li>
</ul>
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