Supports-Loading-Mode header

The HTTP Supports-Loading-Mode response header allows a response to opt-in to being loaded in a novel, higher-risk context that it would otherwise fail to be loaded in.

Header type	[Response header](https://developer.mozilla.org/en-US/docs/Glossary/Response%20header)
[CORS-safelisted response header](https://developer.mozilla.org/en-US/docs/Glossary/CORS-safelisted%20response%20header)	No

Syntax

Supports-Loading-Mode: <client-hint-headers>

Directives

The Supports-Loading-Mode header value is a list of one or more tokens, which can include the following values:

credentialed-prerender
- : Indicates that a destination origin opts in to loading documents via cross-origin, same-site prerendering.
fenced-frame
- : The response can be loaded inside a fenced frame. Without this explicit opt-in, all navigations inside of a fenced frame will fail.

Examples

Supports-Loading-Mode: fenced-frame

HTTP: Hypertext Transfer Protocol

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Reason: CORS header 'Access-Control-Allow-Origin' does not match 'xyz

Reason: CORS request did not succeed

Reason: CORS disabled

Reason: CORS request external redirect not allowed

Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Headers

Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Methods

Reason: Did not find method in CORS header 'Access-Control-Allow-Methods

Reason: expected 'true' in CORS header 'Access-Control-Allow-Credentials

Reason: missing token 'xyz' in CORS header 'Access-Control-Allow-Headers' from CORS preflight channel

Reason: CORS header 'Access-Control-Allow-Origin' missing

Reason: Multiple CORS header 'Access-Control-Allow-Origin' not allowed

Reason: Credential is not supported if the CORS header 'Access-Control-Allow-Origin' is '*

Reason: CORS header 'Origin' cannot be added

Reason: CORS preflight channel did not succeed

Reason: CORS request not HTTP

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Content Security Policy: The page's settings blocked the loading of a resource: xyz

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