FeaturePolicy.allowedFeatures()

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

The allowedFeatures() method of the FeaturePolicy interface returns a list of directive names of all features allowed by the feature policy.enables introspection of individual directives of the Feature Policy it is run on. As such, allowedFeatures() method returns a subset of directives returned by features().

Syntax

const allowed = FeaturePolicy.allowedFeatures()

Parameters

None.

Return value

An array of strings representing the Feature Policy directive names that are allowed by the Feature Policy this method is called on.

Example

The followin example logs all the allowed directives for the current document. Please note that these features might be restricted by the Permissions API, if the user did not grant the corrsponding permission yet.

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

// Then query feature for specific
const allowed = featurePolicy.allowedFeatures()

for (const directive of allowed){
  console.log(directive)
}

Specifications

Specification Status Comment
Feature Policy
The definition of 'allowsFeature' in that specification.
Editor's Draft Initial definition.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
allowedFeatures
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 79Firefox 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 NoOpera 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 NoWebView Android Full support 74Chrome 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 NoSamsung 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.