FormData.has

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

Syntax

formData.has(name);

Parameters

name

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

Returns

A Boolean.

Example

The following line creates an empty FormData object:

var formData = new FormData();

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

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

Specifications

Specification	Status	Comment
XMLHttpRequest The definition of 'has()' in that specification.	Living Standard

Browser compatibility

See also

• XMLHTTPRequest
• Using XMLHttpRequest
• Using FormData objects
• <form>