Web/API/PublicKeyCredential/getClientExtensionResults

Secure contextThis feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

getClientExtensionResults() is a method of the PublicKeyCredential interface that returns an ArrayBuffer which contains a map between the extensions identifiers and their results after having being processed by the client.

During the creation or fetching of a PublicKeyCredential (respectively via navigator.credentials.create() and navigator.credentials.get()), it is possible to have "custom" processing by the client for different extensions which are respectively given by PublicKeyCredentialCreationOptions.extensions and PublicKeyCredentialRequestOptions.extensions.

Note: Extensions are optional and different browsers may recognize different extensions. All extensions are optional for the client to process them: if a browser does not know of a given extension, that will not cause any failure.

Note: This method may only be used in top-level contexts and will not be available in an <iframe> for example.

Syntax

mapArrayBuffer = publicKeyCredential.getClientExtensionResults()

Parameters

None.

Return value

An ArrayBuffer containing the result of the processing of the different extensions by the client. This object contains a map between the extensions' identifiers and their results from the processing.

Warning! As of March 2019, only appId (used during creation with PublicKeyCredentialRequestOptions.extensions) is supported by Chrome and Edge. Firefox does not seem to support any extension.

Examples

var publicKey = {
  // Here are the extensions (as "inputs")
  extensions: {
    "loc": true, // This extension has been defined to include location information in attestation
    "uvi": true  // user verification index: how the user was verified
  },
  challenge: new Uint8Array(16) /* from the server */,
  rp: {
    name: "Example CORP",
    id  : "login.example.com"
  },
  user: {
    id: new Uint8Array(16) /* from the server */,
    name: "[email protected]",
    displayName: "John Doe"
  },
  pubKeyCredParams: [
    {
      type: "public-key",
      alg: -7
    }
  ]
};

navigator.credentials.create({ publicKey })
  .then(function (newCredentialInfo) {
    var myBuffer = newCredentialInfo.getClientExtensionResults();
    // myBuffer will contain the result of any of the processing of the "loc" and "uvi" extensions
  }).catch(function (err) {
     console.error(err);
  });

Specifications

Specification	Status	Comment
Web Authentication: An API for accessing Public Key Credentials Level 1The definition of 'getClientExtensionResults()' in that specification.	Recommendation	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
`getClientExtensionResults`	Chrome Full support 67 Full support 67 Full support 65 Notes' Disabled' Notes' Only supports USB U2F tokens. Disabled' From version 65: this feature is behind the `Web Authentication API` preference (needs to be set to `Enabled`). To change preferences in Chrome, visit chrome://flags.	Edge Full support 18	Firefox Full support 60 Notes' Full support 60 Notes' Notes' Only supports USB U2F tokens.	IE No support No	Opera No support No	Safari Full support 13	WebView Android Full support 70	Chrome Android Full support 70	Firefox Android Full support 60 Notes' Full support 60 Notes' Notes' Only supports USB U2F tokens.	Opera Android No support No	Safari iOS Full support 13.3	Samsung Internet Android No support No

Legend

Full support: Full support
No support: No support
See implementation notes.': See implementation notes.
User must explicitly enable this feature.': User must explicitly enable this feature.