Request.headers

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.

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

Syntax

JavaScript
var <var>myHeaders</var> = <var>request</var>.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:

JavaScript
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:

JavaScript
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

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 42
41[1]
39 (39)
34[1]
Not supported

29
28[1]

Not supported
Feature Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Phone Opera Mobile Safari Mobile Chrome for Android
Basic support Not supported Not supported Not supported Not supported Not supported Not supported Not supported

[1] This feature is implemented behind a preference.

See also

License

© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/request/headers

API Experimental Fetch Headers Property Reference request