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Headers.keys

The Headers.keys() method returns an iterator allowing to go through all keys contained in this object. The keys are ByteString objects.

Note: This method is available in Web Workers.

Syntax

headers.keys();

Return value

Returns an iterator.

Example

// Create a test Headers object
var myHeaders = new Headers();
myHeaders.append('Content-Type', 'text/xml');
myHeaders.append('Vary', 'Accept-Language');

// Display the keys
for(var key of myHeaders.keys()) {
   console.log(key); 
}

The result is:

content-type
vary

Specifications

Specification Status Comment
Fetch
The definition of 'Headers.keys() (as iterator<>)' in that specification.
Living Standard Initial definition

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support 45 16 44 (44) ? 32 ?
Feature Android Webview Chrome for Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support 45 45 44.0 (44) (Yes) ? 32 ?

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/Headers/keys