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Headers: get() method

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

js

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. The name is case-insensitive.

Return value

A String sequence representing the values of the retrieved header or null if this header is not set.

Examples

Creating an empty Headers object is simple:

js

const myHeaders = new Headers(); // Currently empty
myHeaders.get("Not-Set"); // Returns null

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

js

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:

js

myHeaders.append("Accept-Encoding", "deflate");
myHeaders.append("Accept-Encoding", "gzip");
myHeaders.get("Accept-Encoding"); // Returns "deflate, gzip"
myHeaders
  .get("Accept-Encoding")
  .split(",")
  .map((v) => v.trimStart()); // Returns [ "deflate", "gzip" ]

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
get
42Before version 57, get() returns only the first value for the specified header.
14
39Before version 52, get() returns only the first value for the specified header.
No
29Before version 44, get() returns only the first value for the specified header.
10.1
42Before version 57, get() returns only the first value for the specified header.
42Before version 57, get() returns only the first value for the specified header.
39Before version 52, get() returns only the first value for the specified header.
29Before version 43, get() returns only the first value for the specified header.
10.3
4.0Before version 7.0, get() returns only the first value for the specified header.

See also

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https://developer.mozilla.org/en-US/docs/Web/API/Headers/get