Directive: prefetch src

Overview

Caution

Obsolete: The prefetch-src directive existed in an earlier draft of the CSP Level 3 (Draft) specification, but was removed.

The prefetch-src directive was meant to restrict link rel=prefetch and link rel=prerender before it was removed from the spec — the latter of which has been removed from the HTML specification. In its place, see the Speculation Rules API.

Affects: <link rel=prefetch> and <link rel=prerender>

Required reading:

• Can I use prefetch-src?
• MDN Web Docs reference

Fallbacks

✅ prefetch-src will fallback to default-src if it is undefined.

• default-src
  • prefetch-src

Possible errors

• CSP-0803 — [ERROR] directive %s was experimental in CSP3, but should now be removed from CSP policies

References

• MDN Web Docs reference
• Can I use prefetch-src?