Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The HTTP Content-Security-Policy (CSP) fenced-frame-src directive specifies valid sources for nested browsing contexts loaded into <fencedframe> elements.CSP version 1 Directive type Fetch directive Fallback If this directive is absent, the user agent will look for the frame-src directive (which falls back to the child-src directive).
Content-Security-Policy: fenced-frame-src <source-expression-list>;<source-expression-list>A space-separated list of source expression values. Resources of this type may be loaded if they match any of the given source expressions. For this directive, the following source expression values are applicable:
<host-source> value "https:"<scheme-source> value "https:""*"Given this CSP header:
Content-Security-Policy: fenced-frame-src https://example.com/The following sources will not load in a fenced frame:
https://not-example.com/ (domain doesn't match)https://example.org/ (TLD doesn't match)