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
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
headers | Chrome
Full support
42
| Edge Full support 14 | Firefox
Full support
39
| IE No support No | Opera
Full support
29
| Safari No support No | WebView Android No support No | Chrome Android No support 42 — 46 | Firefox Android No support No | Opera Android
Full support
29
| Safari iOS No support No | 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.