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Content-Security-Policy: child-src directive

files/en-us/web/http/reference/headers/content-security-policy/child-src/index.md

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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.

<table class="properties"> <tbody> <tr> <th scope="row">CSP version</th> <td>2</td> </tr> <tr> <th scope="row">Directive type</th> <td>{{Glossary("Fetch directive")}}</td> </tr> <tr> <th scope="row">{{CSP("default-src")}} fallback</th> <td> Yes. If this directive is absent, the user agent will look for the <code>default-src</code> directive. </td> </tr> </tbody> </table>

Syntax

http
Content-Security-Policy: child-src 'none';
Content-Security-Policy: child-src <source-expression-list>;

This directive may have one of the following values:

  • 'none'
    • : No resources of this type may be loaded. The single quotes are mandatory.
  • <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:

Examples

Violation cases

Given this CSP header:

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

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

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

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

  • {{HTTPHeader("Content-Security-Policy")}}
  • {{HTMLElement("frame")}} and {{HTMLElement("iframe")}}
  • {{domxref("Worker")}}, {{domxref("SharedWorker")}}, {{domxref("ServiceWorker")}}