Web/API/FeaturePolicy/allowsFeature

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The allowsFeature() method of the FeaturePolicy interface enables introspection of individual directives of the Feature Policy it is run on. It returns a Boolean that is true if and only if the specified feature is allowed in the specified context (or the default context if no context is specified).

Syntax

const allowed = FeaturePolicy.allowsFeature(<feature>)

or

const allowed = FeaturePolicy.allowsFeature(<feature>, <origin>)

Parameters

`Feature name`

A specific feature name must be specified.

`Origin name` Optional

An origin URL to check the feature on. If it is omitted the default origin is used.

Return value

A Boolean that is true if and only if the feature is allowed.

Example

The following example queries whether or not the document is allowed to use camera API by the Feature Policy. Please note that Camera API might be restricted by the Permissions API, if the user did not grant the corresponding permission yet.

// First, get the Feature Policy object
const featurePolicy = document.featurePolicy

// Then query feature for specific 
const allowed = featurePolicy.allowsFeature("camera")

if (allowed){
  console.log("FP allows camera.")
} else {
  console.log("FP does not allows camera.")
}

Specifications

Specification	Status	Comment
Permissions PolicyThe definition of 'allowsFeature' in that specification.	Editor's Draft	Initial definition.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`allowsFeature` Experimental'	Chrome Full support 74 Full support 74 No support 69 — 73 Disabled' Disabled' From version 69 until version 73 (exclusive): this feature is behind the `#enable-experimental-productivity-features` preference (needs to be set to `Enabled`). To change preferences in Chrome, visit chrome://flags.	Edge Full support 79	Firefox Full support 65 Disabled' Full support 65 Disabled' Disabled' From version 65: this feature is behind the `dom.security.featurePolicy.webidl.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 62 Full support 62 No support 56 — 62 Disabled' Disabled' From version 56 until version 62 (exclusive): this feature is behind the `#enable-experimental-productivity-features` preference (needs to be set to `Enabled`).	Safari No support No	WebView Android Full support 74	Chrome Android Full support 74 Full support 74 No support 69 — 74 Disabled' Disabled' From version 69 until version 74 (exclusive): this feature is behind the `#enable-experimental-productivity-features` preference (needs to be set to `Enabled`). To change preferences in Chrome, visit chrome://flags.	Firefox Android Full support 65 Disabled' Full support 65 Disabled' Disabled' From version 65: this feature is behind the `dom.security.featurePolicy.webidl.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Opera Android Full support 48 Disabled' Full support 48 Disabled' Disabled' From version 48: this feature is behind the `#enable-experimental-productivity-features` preference (needs to be set to `Enabled`).	Safari iOS No support No	Samsung Internet Android Full support 11.0

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.': User must explicitly enable this feature.

FeaturePolicy.allowsFeature() by Mozilla Contributors is licensed under CC-BY-SA 2.5.