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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 |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|
| Basic support | 42 41[1] |
39 (39) 34[1] |
Not supported |
29 |
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.