PublicKeyCredential: isConditionalMediationAvailable() static method

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

The isConditionalMediationAvailable() static method of the PublicKeyCredential interface returns a Promise which resolves to true if conditional mediation is available.

Conditional mediation, if available, results in any discovered credentials being presented to the user in a non-modal dialog box along with an indication of the origin requesting credentials. This is requested by including mediation: 'conditional' in your get() call. In practice, this means autofilling available credentials; you need to include autocomplete="webauthn" on your form fields so that they will show the WebAuthn sign-in options.

A conditional get() call does not show the browser UI and remains pending until the user picks an account to sign-in with from available autofill suggestions:

  • If the user makes a gesture outside of the dialog, it closes without resolving or rejecting the Promise and without causing a user-visible error condition.
  • If the user selects a credential, that credential is returned to the caller.

The prevent silent access flag (see CredentialsContainer.preventSilentAccess()) is treated as being true regardless of its actual value: the conditional behavior always involves user mediation of some sort if applicable credentials are discovered.

Note: If no credentials are discovered, the non-modal dialog will not be visible, and the user agent can prompt the user to take action in a way that depends on the type of credential (for example, to insert a device containing credentials).

Syntax

js

isConditionalMediationAvailable()

Parameters

None.

Return value

A Promise which resolves to a boolean value indicating whether or not conditional mediation is available.

Examples

Before invoking a conditional WebAuthn API call, check if:

  • The browser supports the Web Authentication API.
  • The browser supports WebAuthn conditional UI.

js

// Availability of `window.PublicKeyCredential` means WebAuthn is usable.
if (
  window.PublicKeyCredential &&
  PublicKeyCredential.isConditionalMediationAvailable
) {
  // Check if conditional mediation is available.
  const isCMA = await PublicKeyCredential.isConditionalMediationAvailable();
  if (isCMA) {
    // Call WebAuthn authentication
    const publicKeyCredentialRequestOptions = {
      // Server generated challenge
      challenge: ****,
      // The same RP ID as used during registration
      rpId: "example.com",
    };

    const credential = await navigator.credentials.get({
      publicKey: publicKeyCredentialRequestOptions,
      signal: abortController.signal,
      // Specify 'conditional' to activate conditional UI
      mediation: "conditional",
    });
  }
}

Note: See Sign in with a passkey through form autofill for more information about using conditional mediation.

Specifications

Specification
Web Authentication: An API for accessing Public Key Credentials - Level 3
# dom-publickeycredential-isconditionalmediationavailable

Browser compatibility

BCD tables only load in the browser