index.md

title	short-title	slug	page-type	browser-compat
Response: formData() method	formData()	Web/API/Response/formData	web-api-instance-method	api.Response.formData

{{APIRef("Fetch API")}}

The formData() method of the {{domxref("Response")}} interface takes a {{domxref("Response")}} stream and reads it to completion. It returns a promise that resolves with a {{domxref("FormData")}} object.

Note

This is mainly relevant to service workers. If a user submits a form and a service worker intercepts the request, you could for example call formData() on it to obtain a key-value map, modify some fields, then send the form onwards to the server (or use it locally).

Syntax

formData()

Parameters

None.

Return value

A {{jsxref("Promise")}} that resolves with a {{domxref("FormData")}} object.

Exceptions

• {{domxref("DOMException")}} AbortError
  • : The request was aborted.
• {{jsxref("TypeError")}}
  • : Thrown for one of the following reasons:
    • The response body is disturbed or locked.
    • There was an error decoding the body content (for example, because the {{httpheader("Content-Encoding")}} header is incorrect).
    • The {{glossary("MIME")}} type of the body cannot be determined from the {{httpheader("Content-Type")}} headers included in the response.
    • The body cannot be parsed as a FormData object.

Examples

TBD.

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• ServiceWorker API
• HTTP access control (CORS)
• HTTP