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The headers read-only property of the Request interface contains the Headers object associated with the request.


var myHeaders = request.headers;


A Headers object.


In the following snippet, we create a new request using the Request.Request() constructor (for an image file in the same directory as the script), then save the request headers in a variable:

var myRequest = new Request('flowers.jpg');
var myHeaders = myRequest.headers; // Headers {}

To add a header to the Headers object we use Headers.append; we then create a new Request along with a 2nd init parameter, passing headers in as an init option:

var myHeaders = new Headers();
myHeaders.append('Content-Type', 'image/jpeg');

var myInit = { method: 'GET',
                   headers: myHeaders,
                   mode: 'cors',
                   cache: 'default' };

var myRequest = new Request('flowers.jpg',myInit);

myContentType = myRequest.headers.get('Content-Type'); // returns 'image/jpeg'


Specification Status Comment
The definition of 'headers' in that specification.
Living Standard Initial definition

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 42
(Yes) 39 (39)
No support


No support
Feature Android Edge Firefox Mobile (Gecko) Firefox OS (Gecko) IE Phone Opera Mobile Safari Mobile Chrome for Android
Basic support No support (Yes) No support No support No support No support No support No support

[1] This feature is implemented behind a preference.

See also

Document Tags and Contributors

 Contributors to this page: chrisdavidmills, abbycar, Sebastianz, kscarfone
 Last updated by: chrisdavidmills,