Revision 1065826 of CSSStyleSheet

<div>{{APIRef("CSSOM")}}</div>

<p>The <code>CSSStyleSheet</code> interface represents a single <a href="/en-US/docs/Web/CSS">CSS</a> style sheet. It inherits properties and methods from its parent, {{domxref("StyleSheet")}}.</p>

<p>A style sheet consists of <em>{{domxref("CSSRule", "rules", "", 1)}}</em>, such as <em>{{domxref("CSSStyleRule", "style rules", "", 1)}}</em><em> </em>("<code>h1,h2 { font-size: 16pt }"</code>), various <em>at-rules</em> (<code>@import</code>, <code>@media</code>, ...), etc. This interface lets you inspect and modify the list of rules in the stylesheet.</p>

<h2 id="Properties">Properties</h2>

<p><em>Inherits properties from its parent, {{domxref("Stylesheet")}}.</em></p>

<dl>
 <dt id="cssRules">{{domxref("CSSStyleSheet.cssRules")}}</dt>
 <dd>Returns a live {{domxref("CSSRuleList")}}, listing the {{domxref("CSSRule")}} objects in the style sheet.<br />
 This is normally used to access individual rules like this: <code>styleSheet.cssRules[i]</code> (where <code>i = 0..cssRules.length</code>).<br />
 To add or remove items in <code>cssRules</code>, use the&nbsp;<code>CSSStyleSheet</code>'s <code>deleteRule()</code> and <code>insertRule()</code> methods, described below.</dd>
 <dt id="ownerRule">{{domxref("CSSStyleSheet.ownerRule")}}</dt>
 <dd>If this style sheet is imported into the document using an {{cssxref("@import")}} rule, the <code>ownerRule</code> property will return that {{domxref("CSSImportRule")}}, otherwise it returns <code>null</code>.</dd>
</dl>

<h2 id="Methods">Methods</h2>

<p><em>Inherits methods from its parent, {{domxref("Stylesheet")}}.</em></p>

<dl>
 <dt id="deleteRule">{{domxref("CSSStyleSheet.deleteRule")}}</dt>
 <dd>Deletes a rule at the specified position from the style sheet.</dd>
 <dt id="insertRule">{{domxref("CSSStyleSheet.insertRule")}}</dt>
 <dd>Inserts a new rule at the specified position in the style sheet, given the textual representation of the rule.</dd>
</dl>

<h2 id="Notes">Notes</h2>

<p>In some browsers, if a stylesheet is loaded from a different domain, calling <code>cssRules</code> results in <code>SecurityError</code>.</p>

<p>A stylesheet is associated with at most one {{domxref("Document")}}, which it applies to (unless {{domxref("StyleSheet.disabled", "disabled", "", 1)}}). A list of <code>CSSStyleSheet</code> objects for a given document can be obtained using the {{domxref("document.styleSheets")}} property. A specific style sheet can also be accessed from its <em>owner</em> object (<code>Node</code> or <code>CSSImportRule</code>), if any.</p>

<p>A <code>CSSStyleSheet</code> object is created and inserted into the document's <code>styleSheets</code> list automatically by the browser, when a style sheet is loaded for a document. As the {{domxref("document.styleSheets")}} list cannot be modified directly, there's no useful way to create a new <code>CSSStyleSheet</code> object manually (although <a href="https://tabatkins.github.io/specs/construct-stylesheets/">Constructable Stylesheet Objects</a> might get added to the Web APIs at some point).</p>

<p>A (possibly incomplete) list of ways a style sheet can be associated with a document follows:</p>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Reason for the style sheet to be associated with the document</th>
   <th scope="col">Appears in <code>document.<br />
    styleSheets</code> list</th>
   <th scope="col">Getting the owner element/rule given the style sheet object</th>
   <th scope="col">The interface for the owner object</th>
   <th scope="col">Getting the CSSStyleSheet object from the owner</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{HTMLElement("style")}} and {{HTMLElement("link")}} elements in the document</td>
   <td>Yes</td>
   <td>{{domxref("StyleSheet.ownerNode", ".ownerNode")}}</td>
   <td>{{domxref("HTMLLinkElement")}},<br />
    {{domxref("HTMLStyleElement")}},<br />
    or {{domxref("SVGStyleElement")}}</td>
   <td>{{domxref("LinkStyle.sheet", ".sheet")}}</td>
  </tr>
  <tr>
   <td>CSS&nbsp;{{cssxref("@import")}} rule in other style sheets applied to the document</td>
   <td>Yes</td>
   <td>{{domxref("CSSStyleSheet.ownerRule", ".ownerRule")}}</td>
   <td>{{domxref("CSSImportRule")}}</td>
   <td>{{domxref("CSSImportRule.styleSheet", ".styleSheet")}}</td>
  </tr>
  <tr>
   <td><code>&lt;?xml-stylesheet ?&gt;</code> processing instruction in the (non-HTML) document</td>
   <td>Yes</td>
   <td>{{domxref("StyleSheet.ownerNode", ".ownerNode")}}</td>
   <td>{{domxref("ProcessingInstruction")}}</td>
   <td>{{domxref("LinkStyle.sheet", ".sheet")}}</td>
  </tr>
  <tr>
   <td>HTTP Link Header</td>
   <td>Yes</td>
   <td><em>N/A</em></td>
   <td>N/A</td>
   <td>N/A</td>
  </tr>
  <tr>
   <td>User agent (default) style sheets</td>
   <td>No</td>
   <td>N/A</td>
   <td>N/A</td>
   <td>N/A</td>
  </tr>
 </tbody>
</table>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th>Specification</th>
   <th>Status</th>
   <th>Comment</th>
  </tr>
  <tr>
   <td>{{SpecName("CSSOM", "#cssstylesheet", 'CSSStyleSheet')}}</td>
   <td>{{Spec2("CSSOM")}}</td>
   <td>&nbsp;</td>
  </tr>
  <tr>
   <td>{{SpecName("DOM2 Style", "css.html#CSS-CSSStyleSheet", "CSSStyleSheet")}}</td>
   <td>{{Spec2("DOM2 Style")}}</td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p>{{CompatibilityTable}}</p>

<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>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>9.0</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</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&nbsp;Phone</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li>{{domxref("StyleSheet")}}</li>
</ul>