Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
Warning: This directive is marked as obsolete in the specification: all mixed content is now blocked if it can't be autoupgraded.
block-all-mixed-content directive prevents loading any assets over HTTP when the page uses HTTPS.
All mixed content resource requests are blocked, including both active and passive mixed content.
This also applies to
<iframe> documents, ensuring the entire page is mixed content-free.
upgrade-insecure-requests directive is evaluated before
If the former is set, the latter does nothing, so set one directive or the other – not both, unless you want to force HTTPS on older browsers that do not force it after a redirect to HTTP.
Content-Security-Policy: block-all-mixed-content; <meta http-equiv="Content-Security-Policy" content="block-all-mixed-content">
To disallow http assets on a more granular level, you can also set individual directives to
For example, to disallow insecure HTTP images:
Content-Security-Policy: img-src https:
Not part of any current specification. Used to be defined in the outdated Mixed Content Level 1 specification.
BCD tables only load in the browser