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Headers.getAll

Obsolete since Gecko 52 (Firefox 52 / Thunderbird 52 / SeaMonkey 2.49)
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage 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 specification changes.

The getAll() method of the Headers interface used to return an array of all the values of a header within a Headers object with a given name; in newer versions of the Fetch spec, it has been deleted, and Headers.get() has been updated to fetch all header values instead of only the first one.

If the requested header doesn't exist in the Headers object, it returns an empty array.

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

Syntax

myHeaders.getAll(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

An Array containing 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 getAll():

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

If the header has multiple values associated with it, the array 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.getAll('Accept-Encoding'); // Returns [ "deflate", "gzip" ]

Note: Use Headers.get to return only the first value added to the Headers object.

Specifications

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

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 42
41 behind pref
39 (39)
34 behind pref
No support

29
28 behind pref

No support
Feature Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Phone Opera Mobile Safari Mobile Chrome for Android
Basic support No support No support No support No support No support No support No support

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/Headers/getAll