CSSStyleSheet()

The CSSStyleSheet() constructor creates a new CSSStyleSheet object which represents a single Stylesheet.

After constructing a stylesheet the CSSStyleSheet.replace(), CSSStyleSheet.replaceSync(), CSSStyleSheet.insertRule(), and CSSStyleSheet.deleteRule() methods can be used to modify the rules of the new stylesheet.

A stylesheet created using this method is referred to as a “constructed stylesheet”. A constructed stylesheet can be shared between a document and its shadow DOM subtrees using ShadowRoot.adoptedStyleSheets and Document.adoptedStyleSheets.

Inputs: options An object containing the following: baseURL A string containing the baseURL used to resolve relative URLs in the stylesheet. media A MediaList containing a list of media rules, or a string containing a single rule. disabled A Boolean indicating whether the stylesheet is disabled. False by default.