W3cubDocs

/DOM

XMLHttpRequest.getAllResponseHeaders

The XMLHttpRequest.getAllResponseHeaders() method returns all the response headers, separated by CRLF, as a string, or null if no response has been received. If a network error happened, an empty string is returned.

Note: For multipart requests, this returns the headers from the current part of the request, not from the original channel.

Syntax

var headers = XMLHttpRequest.getAllResponseHeaders();

Parameters

None.

Return value

A ByteString representing all of the response's headers (except those whose field name is Set-Cookie or Set-Cookie2) separated by CRLF, or null if no response has been received. If a network error happened, an empty string is returned.

Example

var request = new XMLHttpRequest();
request.open("GET", "foo.txt", true);
request.send();
request.onreadystatechange = function() {
  if(this.readyState == this.HEADERS_RECEIVED) {

    //
    // RAW STRING OF HEADERS
    //
    var headers = request.getAllResponseHeaders();
    console.log(headers);
    // "date: Fri, 08 Dec 2017 21:04:30 GMT\r\ncontent-encoding: gzip\r\nx-content-type-options: nosniff\r\nserver: meinheld/0.6.1\r\nx-frame-options: DENY\r\ncontent-type: text/html; charset=utf-8\r\nconnection: keep-alive\r\nstrict-transport-security: max-age=63072000\r\nvary: Cookie, Accept-Encoding\r\ncontent-length: 6503\r\nx-xss-protection: 1; mode=block\r\n"


    //
    // ARRAY OF HEADERS
    //
    var arr = headers.trim().split(/[\r\n]+/);


    //
    // MAP OF HEADERS
    //
    var map = {};
    arr.forEach(function (line) {
      var parts = line.split(': ');
      var header = parts.shift();
      var value = parts.join(': ');
      map[header] = value;
    });

  }
}

Specifications

Specification	Status	Comment
XMLHttpRequest The definition of 'getAllResponseHeaders()' in that specification.	Living Standard	WHATWG living standard

Browser compatibility

Feature	Chrome	Edge	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	1	(Yes)	1.0 (1.7 or earlier)^[1]	5^[2] 7	(Yes)	1.2

Feature	Android	Chrome for Android	Edge	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	?	1.0	(Yes)	1.0 (1.0)	?	?	?

[1] Starting from Firefox 49, empty headers are returned as empty strings in case the preference network.http.keep_empty_response_headers_as_empty_string is set to true, defaulting to false. Before Firefox 49 empty headers had been ignored. Since Firefox 50 the preference defaults to true.

[2] This feature was implemented via ActiveXObject(). Internet Explorer implements the standard XMLHttpRequest since version 7.