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.
Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
prefetch-src directive specifies valid resources that may
be prefetched or prerendered.
One or more sources can be allowed for the
Content-Security-Policy: prefetch-src <source>; Content-Security-Policy: prefetch-src <source> <source>;
Given a page with the following Content Security Policy:
Content-Security-Policy: prefetch-src https://example.com/
Fetches for the following code will return network errors, as the URLs provided do not
prefetch-src's source list:
<link rel="prefetch" href="https://example.org/" /> <link rel="prerender" href="https://example.org/" />
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spec_url to mdn/browser-compat-data. Also make sure the specification is included in w3c/browser-specs.
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