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

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Experimental
Chrome Full support 45Edge Full support 16Firefox Full support 44IE ? Opera Full support 32Safari ? WebView Android Full support 45Chrome Android Full support 45Edge Mobile Full support YesFirefox Android Full support 44Opera Android Full support 32Safari iOS ? Samsung Internet Android Full support 5.0

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.

See also

Document Tags and Contributors

Last updated by: sideshowbarker,