Web/API/PasswordCredential/additionalData

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

DeprecatedThis feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

The additionalData property of the PasswordCredential interface takes one of a FormData instance, a URLSearchParams instance, or null. The data in the objects will be added to the request body and sent to the remote endpoint with the credentials.

Syntax

passwordCredential.additionalData = formData
formData = passwordCredential.additionalData
passwordCredential.additionalData = urlSearchParams
ulrSearchParams = passwordCredential.additionalData

Value

One of a FormData instance, a URLSearchParams instance, or null.

Example

The following example creates a FormData object with an appended CSRF token. It then stores the form object in the additionalData parameter, before sending it to server in a call to fetch.

//The options object was previously created. 
navigator.credentials.get(options).then(function(creds) {
  if (creds.type == 'password') {
    var form = new FormData();
    var csrf_token = document.querySelector('csrf_token').value;
    form.append('csrf_token', csrf_token);

    creds.additionalData = form;

    fetch('https://www.example.com', {
      method: 'POST',
      credentials: creds
    });
  };
});

Specifications

Specification	Status	Comment
Credential Management Level 1	Working Draft	Initial definition.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

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
additionalData Experimental'Deprecated'	Chrome Full support 51	Edge Full support ≤79	Firefox ?	IE No support No	Opera Full support 38	Safari ?	WebView Android Full support 51	Chrome Android Full support 51	Firefox Android ?	Opera Android Full support 41	Safari iOS ?	Samsung Internet Android Full support 5.0

Legend

Full support  

Full support

No support  

No support

Compatibility unknown  

Compatibility unknown

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

Deprecated. Not for use in new websites.'

Deprecated. Not for use in new websites.

PasswordCredential.additionalData by Mozilla Contributors is licensed under CC-BY-SA 2.5.