FormData.has() - Web APIs 编辑

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

Note: This method is available in Web Workers.

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

Browser compatibility

BCD tables only load in the browser

See also

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