Constructed stylesheetsBaseline · Widely available
The CSSStyleSheet constructor creates a new stylesheet which can be shared between a document and multiple shadow roots using adoptedStyleSheets.
Supported in all major browsers for at least 30 months — safe to use without fallbacks. Baseline since Mar 27, 2023. Widely available since Sep 27, 2025.
Browser support
DesktopChrome
1–72Not supported
73+Supportedsince Mar 12, 2019
Current: 155Edge
12–18Not supported
79+Supportedsince Jan 15, 2020
Current: 154Firefox
1–100Not supported
101+Supportedsince May 31, 2022
Current: 157Safari
1–16.3Not supported
16.4+Supportedsince Mar 27, 2023
Current: 27MobileChrome Android
18–72Not supported
73+Supportedsince Mar 12, 2019
Current: 155Firefox Android
4–100Not supported
101+Supportedsince May 31, 2022
Current: 157Safari iOS
1–16.3Not supported
16.4+Supportedsince Mar 27, 2023
Current: 27How to use
This feature is Baseline widely available — use it freely, no fallback needed.
Example
Full syntax and examples are on MDN: CSSStyleSheet.
Feature detection
JS · check before using
if ("CSSStyleSheet" in globalThis && "CSSStyleSheet" in CSSStyleSheet.prototype) {
// CSSStyleSheet.CSSStyleSheet is available
}Sub-features
Support for each part of the feature (6). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| CSSStyleSheet.CSSStyleSheet | 73 | 79 | 101 | 16.4 | 73 | 101 | 16.4 |
| CSSStyleSheet.CSSStyleSheet.options_baseURL_parameter | ✕ | ✕ | 101 | 16.4 | ✕ | 101 | 16.4 |
| CSSStyleSheet.replace | 73 | 79 | 101 | 16.4 | 73 | 101 | 16.4 |
| CSSStyleSheet.replaceSync | 73 | 79 | 101 | 16.4 | 73 | 101 | 16.4 |
| Document.adoptedStyleSheets | 73 | 79 | 101 | 16.4 | 73 | 101 | 16.4 |
| ShadowRoot.adoptedStyleSheets | 73 | 79 | 101 | 16.4 | 73 | 101 | 16.4 |