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"

Specifications

Browser compatibility

[1] 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.

See also

• ServiceWorker API
• HTTP access control (CORS)
• HTTP