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
Fetch The definition of 'headers' in that specification.	Living Standard	Initial definition

Browser compatibility

[1] This feature is implemented behind a preference.

See also

• ServiceWorker API
• HTTP access control (CORS)
• HTTP