Headers.get()

The get() method of the Headers interface returns a byte string of all the values of a header within a Headers object with a given name. If the requested header doesn't exist in the Headers object, it returns null.

For security reasons, some headers can only be controlled by the user agent. These headers include the forbidden header names  and forbidden response header names.

Syntax

myHeaders.get(name);

Parameters

name
The name of the HTTP header whose values you want to retrieve from the Headers object. If the given name is not the name of an HTTP header, this method throws a TypeError.

Returns

A ByteString sequence representing the values of the retrieved header.

Example

Creating an empty Headers object is simple:

var myHeaders = new Headers(); // Currently empty

You could add a header to this using Headers.append, then retrieve it using get():

myHeaders.append('Content-Type', 'image/jpeg');
myHeaders.get('Content-Type'); // Returns "image/jpeg"

If the header has multiple values associated with it, the byte string will contain all the values, in the order they were added to the Headers object:

myHeaders.append('Accept-Encoding', 'deflate');
myHeaders.append('Accept-Encoding', 'gzip');
myHeaders.get('Accept-Encoding'); // Returns "deflate,gzip"

Note: Headers.getAll used to have this functionality, with Headers.get returning only the first value added to the Headers object. The latest spec has removed getAll(), and updated get() to return all values.

Specifications

Specification Status Comment
Fetch
The definition of 'get()' in that specification.
Living Standard  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support

42

412

Yes

523

39

344

No

29

285

10.1
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support

42

411

42

412

Yes No

29

285

No ?

1. From version 41: this feature is behind the Experimental Web Platform Features preference.

2. From version 41: this feature is behind the Experimental Web Platform Features preference. To change preferences in Chrome, visit chrome://flags.

3. Prior to Firefox 52, get() only returned the first value in the specified header, with getAll() returning all values. From 52 onwards, get() now returns all values and getAll() has been deleted.

4. From version 34: this feature is behind the dom.fetch.enabled preference. To change preferences in Firefox, visit about:config.

5. From version 28: this feature is behind the Experimental Web Platform Features preference.

See also

Document Tags and Contributors

 Last updated by: fscholz,