blocking="render"Limited availability
The blocking="render" attribute for <link>, <script>, and <style> elements blocks rendering until the external script or stylesheet has been loaded. For <link rel="expect">, rendering is blocked until a specific element is in the DOM.
Not yet supported in all major browsers — check the table and provide a fallback.
Browser support
DesktopChrome
1–104Not supported
105+Supportedsince Sep 2, 2022
Current: 155Edge
12–104Not supported
105+Supportedsince Sep 1, 2022
Current: 154Firefox
✕Not supportedup to 157
Current: 157Safari
1–18.1Not supported
18.2+Supportedsince Dec 11, 2024
Current: 27MobileChrome Android
18–104Not supported
105+Supportedsince Sep 2, 2022
Current: 155Firefox Android
✕Not supportedup to 157
Current: 157Safari iOS
1–18.1Not supported
18.2+Supportedsince Dec 11, 2024
Current: 27How to use
Not supported in Firefox, Firefox Android. Use feature detection below and provide a fallback (or a polyfill) for those browsers.
Example
Full syntax and examples are on MDN: blocking.
Feature detection
JS · check before using
if ("HTMLLinkElement" in globalThis && "blocking" in HTMLLinkElement.prototype) {
// HTMLLinkElement.blocking is available
}Documentation (MDN)
Specification
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 |
|---|---|---|---|---|---|---|---|
| HTMLLinkElement.blocking | 105 | 105 | ✕ | 18.2 | 105 | ✕ | 18.2 |
| HTMLScriptElement.blocking | 105 | 105 | ✕ | 18.2 | 105 | ✕ | 18.2 |
| HTMLStyleElement.blocking | 105 | 105 | ✕ | 18.2 | 105 | ✕ | 18.2 |
| link.blocking | 105 | 105 | ✕ | 18.2 | 105 | ✕ | 18.2 |
| script.blocking | 105 | 105 | ✕ | 18.2 | 105 | ✕ | 18.2 |
| style.blocking | 105 | 105 | ✕ | 18.2 | 105 | ✕ | 18.2 |