The autofill.trigger command

syntax

Command definition quoted verbatim (CDDL) from spec §7.1.1:

autofill.Trigger = (
  method: "autofill.trigger",
  params: autofill.TriggerParameters
)

autofill.TriggerParameters = {
  context: browsingContext.BrowsingContext,
  element: script.SharedReference,
  ? card: autofill.Card,
  ? address: autofill.Address
}

autofill.Card = {
  number: text,
  name: text,
  expiryMonth: text,
  expiryYear: text,
  cvc: text
}

autofill.Address = {
  fields: [ * autofill.Field ]
}

autofill.Field = {
  name: autofill.FieldName,
  value: text
}

autofill.FieldName is the enumeration "name" / "honorific-prefix" / "given-name" / "additional-name" / "family-name" / "honorific-suffix" / "nickname" / "organization" / "street-address" / "address-line1" / "address-line2" / "address-line3" / "address-level4" / "address-level3" / "address-level2" / "address-level1" / "country" / "country-name" / "postal-code" / "tel" / "tel-country-code" / "tel-national" / "tel-area-code" / "tel-local" / "email" — corresponding to the HTML autofill field names.

parameters

Exactly one of card / address must be present — both, or neither, is an invalid argument error (processing steps 10–11).

return value

Return type EmptyResult: on success the remote end returns success with data null (final processing step). The command reports no fill details; observe the effect in-page via the autofill event and the resulting control values.

errors

The error codes defined by the processing steps (spec §7.1.2), verbatim:

Earlier steps can also fail with the generic WebDriver BiDi “trying” errors when the browsing context or shared reference cannot be resolved; those come from the referenced WebDriver BiDi algorithms, not this spec.

context and exposure

Not a web-page API: it is a remote-end command available only inside a WebDriver BiDi automation session, defined “for automated testing of autofill functionality” (spec §7). Nothing is exposed to page script; pages only observe the resulting fill and its autofill event.

lifecycle

Processing steps in order (§7.1.2, condensed): resolve the navigable from context → take its active document, settings and realm → deserialize element → validate it is a form control with a form owner → validate exactly one of card/address → check the user agent can perform autofill → parse the payload → the user agent should autofill element and element’s form owner, while taking into account the contents of parsed card and parsed address → return success. The triggered fill then runs the normal firing model, so the page’s autofill listener and refill() behave exactly as in a user-initiated fill.

examples

Both example payloads from the spec, quoted verbatim. Address autofill:

{
  "method": "autofill.trigger",
  "params": {
    "context": "context-id-123",
    "element": { "sharedId": "element-id-456" },
    "address": {
      "fields": [
        { "name": "given-name", "value": "John" },
        { "name": "family-name", "value": "Doe" },
        { "name": "street-address", "value": "123 Main St" },
        { "name": "address-level2", "value": "San Francisco" },
        { "name": "address-level1", "value": "CA" },
        { "name": "postal-code", "value": "94102" },
        { "name": "country", "value": "US" }
      ]
    }
  }
}

Credit-card autofill:

{
  "method": "autofill.trigger",
  "params": {
    "context": "context-id-123",
    "element": { "sharedId": "cc-number-element-id" },
    "card": {
      "number": "4111111111111111",
      "name": "John Doe",
      "expiryMonth": "12",
      "expiryYear": "2028",
      "cvc": "123"
    }
  }
}

browser compatibility

Interim table — explicit unknowns. BCD’s webdriver/bidi/ tree has no autofill module file (webdriver/bidi/autofill.json returns 404 while sibling modules like input.json exist; checked 2026-10-04):

security and privacy

The command injects caller-chosen card/address values, bypassing the user-consent gesture that spec §6 expects for real fills — acceptable only because WebDriver BiDi commands run solely in an automation session the user (or CI) explicitly started; no user profile data is read (the test supplies all values). The spec adds no command-specific security text beyond that session boundary (verified 2026-10-04).

see also

• Autofill event — overview
• AutofillEvent() and AutofillEventInit
• Autofill Event specification (WICG)
• WebDriver BiDi specification
• chromestatus — Autofill event (5137581018841088)