Headers: get() method

Syntax

get(name)

Parameters

name

The name of the HTTP header whose values you want to retrieve from the Headers object. If the given name doesn't match the field-name production in the HTTP specification, 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:

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():

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

Specifications

Browser compatibility

See also

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