--- title: AuthenticatorResponse.clientDataJSON slug: Web/API/AuthenticatorResponse/clientDataJSON translation_of: Web/API/AuthenticatorResponse/clientDataJSON ---
{{APIRef("Web Authentication API")}}{{securecontext_header}}
The clientDataJSON
property of the {{domxref("AuthenticatorResponse")}} interface stores a JSON string in an {{domxref("ArrayBuffer")}}, representing the client data that was passed to {{domxref("CredentialsContainer.create()")}} or {{domxref("CredentialsContainer.get()")}}. This property is only accessed on one of the child objects of AuthenticatorResponse
, specifically {{domxref("AuthenticatorAttestationResponse")}} or {{domxref("AuthenticatorAssertionResponse")}}.
var arrayBuffer = AuthenticatorAttestationResponse.clientDataJSON; var arrayBuffer = AuthenticatorAssertionResponse.clientDataJSON;
An {{jsxref("ArrayBuffer")}}.
After the clientDataJSON
object is converted from an ArrayBuffer
to a JavaScript object, it will have the following properties:
type
"webauthn.get"
when an existing credential is retrieved or "webauthn.create"
when a new credential is created.challenge
origin
tokenBindingId
{{optional_inline}}An object describing the state of the token binding protocol for the communication with the relying party. It has two properties:
status
: A string which is either "supported"
which indicates the client support token binding but did not negotiate with the relying party or "present"
when token binding was used alreadyid
: A {{domxref("DOMString")}} which is the base64url encoding of the token binding ID which was used for the communication.Should this property be absent, it would indicate that the client does not support token binding.
function arrayBufferToStr(buf) { return String.fromCharCode.apply(null, new Uint8Array(buf)); } // pk is a PublicKeyCredential that is the result of a create() or get() Promise var clientDataStr = arrayBufferToStr(pk.clientDataJSON); var clientDataObj = JSON.parse(clientDataStr); console.log(clientDataObj.type); // "webauthn.create" or "webauthn.get" console.log(clientDataObj.challenge); // base64 encoded String containing the original challenge console.log(clientDataObj.origin); // the window.origin
Specification | Status | Comment |
---|---|---|
{{SpecName('WebAuthn','#dom-authenticatorresponse-clientdatajson', 'clientDataJSON')}} | {{Spec2('WebAuthn')}} | Initial definition. |
{{Compat("api.AuthenticatorResponse.clientDataJSON")}}