Headers: CSP.child-src

Content-Security-Policy: child-src directive

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2017.

Learn more
See full compatibility

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

CSP version	2
Directive type	Fetch directive
`default-src` fallback	Yes. If this directive is absent, the user agent will look for the `default-src` directive.

Syntax

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:

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

This <iframe> and worker are blocked and won't load:

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

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

Specifications

Specification
Content Security Policy Level 3> # directive-child-src>

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS
`child-src`	40	15	45	27	10	40	45	27	9.3	4.0	40	9.3