Web/API/Request/headers

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

Syntax

var myHeaders = request.headers;

Value

A Headers object.

Example

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'

Specifications

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

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`headers` Experimental'	Chrome Full support 42 Full support 42 Full support 41 Disabled' Disabled' From version 41: this feature is behind the `Experimental Web Platform Features` preference. To change preferences in Chrome, visit chrome://flags.	Edge Full support 14	Firefox Full support 39 Full support 39 Full support 34 Disabled' Disabled' From version 34: this feature is behind the `dom.fetch.enabled` preference. To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 29 Full support 29 Full support 28 Disabled' Disabled' From version 28: this feature is behind the `Experimental Web Platform Features` preference.	Safari Full support 10.1	WebView Android No support No	Chrome Android No support 42 — 46	Firefox Android No support No	Opera Android Full support 29 Full support 29 Full support 28 Disabled' Disabled' From version 28: this feature is behind the `Experimental Web Platform Features` preference.	Safari iOS Full support 10.3	Samsung Internet Android No support 4.0 — 5.0

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.': User must explicitly enable this feature.