index.md

---

title: "CSP: child-src"
slug: Web/HTTP/Headers/Content-Security-Policy/child-src
browser-compat: http.headers.Content-Security-Policy.child-src

---

{{HTTPSidebar}}

The HTTP {{HTTPHeader("Content-Security-Policy")}} (CSP) child-src directive defines the valid sources for web workers and nested browsing contexts loaded using elements such as {{HTMLElement("frame")}} and {{HTMLElement("iframe")}}. For workers, non-compliant requests are treated as fatal network errors by the user agent.

CSP version	2
Directive type	{{Glossary("Fetch directive")}}
{{CSP("default-src")}} fallback	Yes. If this directive is absent, the user agent will look for the default-src directive.

Syntax

One or more sources can be allowed for the child-src policy:

Content-Security-Policy: child-src <source>;
Content-Security-Policy: child-src <source> <source>;

Sources

<source> can be any one of the values listed in CSP Source Values.

Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a number of other directives).

Examples

Violation cases

Given this CSP header:

Content-Security-Policy: child-src https://example.com/

This {{HTMLElement("iframe")}} and worker are blocked and won't load:

<iframe src="https://not-example.com"></iframe>

<script>
  const blockedWorker = new Worker("data:application/javascript,…");
</script>

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{HTTPHeader("Content-Security-Policy")}}

• {{HTMLElement("frame")}} and {{HTMLElement("iframe")}}

• {{domxref("Worker")}}, {{domxref("SharedWorker")}}, {{domxref("ServiceWorker")}}