Allows developers to selectively enable and disable use of Synchronous XMLHttpRequest requests through the feature policy HTTP header or the <iframe> "allow" attribute. The identifier for the feature in policies is "sync-xhr". By default, synchronous XHR is allowed in all frames. If developers wish to disable this on any page, they can include a header like: Feature-Policy: sync-xhr 'none' Or embed content in an frame with sync XHR disabled like: <iframe src="..." allow="sync-xhr 'none'">
Demos
Documentation
Status in Chromium
Enabled by default
(tracking bug)
Consensus & Standardization
After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.
- Positive
- No signal
- No signals
Owner
Search tags
policy, xhr, synchronous,Last updated on 2021-06-02