This feature is only shown in the feature list to users with edit access.

Allow developers to selectively enable and disable synchronous XMLHttpRequest in documents through Document Policy. 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: Document-Policy: sync-xhr=?0 When disabled in this way, requests to use synchronous XHR will appear to encounter a network error when the send() method is called.

Status in Chromium


No active development

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • No signal
  • No signal
  • No signals


Last updated on 2020-11-09