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

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

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.

Request.headers

Syntax

Value

Example

Specifications

Browser compatibility

See also

Document Tags and Contributors