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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

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

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome Full support 50Edge No support NoFirefox Full support 39IE No support NoOpera Full support YesSafari Full support 11WebView Android ? Chrome Android Full support 50Edge Mobile No support NoFirefox Android Full support YesOpera Android Full support YesSafari iOS No support NoSamsung Internet Android ?

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown

See also

文件標籤與貢獻者

最近更新: ExE-Boss,