CSSStyleSheet

The CSSStyleSheet interface represents a single CSS style sheet. It inherits properties and methods from its parent, StyleSheet.

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

See the Notes section for the various ways a CSSStyleSheet object can be obtained.

Properties

Inherits properties from its parent, Stylesheet.

CSSStyleSheet.cssRules

Returns a live CSSRuleList, listing the CSSRule objects in the style sheet.
This is normally used to access individual rules like this:
   styleSheet.cssRules[i] // where i = 0..cssRules.length
To add or remove items in cssRules, use the CSSStyleSheet's deleteRule() and insertRule() methods, described below.

CSSStyleSheet.ownerRule

If this style sheet is imported into the document using an @import rule, the ownerRule property will return that CSSImportRule, otherwise it returns null.

Methods

Inherits methods from its parent, Stylesheet.

CSSStyleSheet.deleteRule

Deletes a rule at the specified position from the style sheet.

CSSStyleSheet.insertRule

Inserts a new rule at the specified position in the style sheet, given the textual representation of the rule.

Notes

In some browsers, if a stylesheet is loaded from a different domain, calling cssRules results in SecurityError.

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

A CSSStyleSheet object is created and inserted into the document's styleSheets list automatically by the browser, when a style sheet is loaded for a document. As the document.styleSheets list cannot be modified directly, there's no useful way to create a new CSSStyleSheet object manually (although Constructable Stylesheet Objects might get added to the Web APIs at some point). To create a new stylesheet, insert a <style> or <link> element into the document.

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

Reason for the style sheet to be associated with the document	Appears in document. styleSheets list	Getting the owner element/rule given the style sheet object	The interface for the owner object	Getting the CSSStyleSheet object from the owner
<style> and <link> elements in the document	Yes	.ownerNode	HTMLLinkElement, HTMLStyleElement, or SVGStyleElement	.sheet
CSS @import rule in other style sheets applied to the document	Yes	.ownerRule	CSSImportRule	.styleSheet
<?xml-stylesheet ?> processing instruction in the (non-HTML) document	Yes	.ownerNode	ProcessingInstruction	.sheet
HTTP Link Header	Yes	N/A	N/A	N/A
User agent (default) style sheets	No	N/A	N/A	N/A

Specifications

Specification	Status	Comment
CSS Object Model (CSSOM) The definition of 'CSSStyleSheet' in that specification.	Working Draft
Document Object Model (DOM) Level 2 Style Specification The definition of 'CSSStyleSheet' in that specification.	Recommendation	Initial definition

Browser compatibility

See also

• Using dynamic styling information