FormData: has() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Note: This feature is available in Web Workers.

The has() method of the FormData interface returns whether a FormData object contains a certain key.

Syntax

js
has(name)

Parameters

name

A string representing the name of the key you want to test for.

Return value

true if a key of FormData matches the specified name. Otherwise, false.

Examples

The following snippet shows the results of testing for the existence of username in a FormData object, before and after appending a username value to it with append():

js
formData.has("username"); // Returns false
formData.append("username", "Chris");
formData.has("username"); // Returns true

Specifications

Specification
XMLHttpRequest
# dom-formdata-has

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
has

Legend

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Full support
Full support

See also