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Request.constructor

The Request() constructor creates a new Request object.

Syntax

var myRequest = new Request(input[, init]);

Parameters

input
Defines the resource that you wish to fetch. This can either be:
  • A USVString containing the direct URL of the resource you want to fetch.
  • A Request object, effectively creating a copy. Note the following behavioural updates to retain security while making the constructor less likely to throw exceptions:
    • If this object exists on another origin to the constructor call, the Request.referrer is stripped out.
    • If this object has a Request.mode of navigate, the mode value is converted to same-origin.
init Optional
An options object containing any custom settings that you want to apply to the request. The possible options are:
  • method: The request method, e.g., GET, POST.
  • headers: Any headers you want to add to your request, contained within a Headers object or an object literal with ByteString values.
  • body: Any body that you want to add to your request: this can be a Blob, BufferSource, FormData, URLSearchParams, USVString, or ReadableStream object. Note that a request using the GET or HEAD method cannot have a body.
  • mode: The mode you want to use for the request, e.g., cors, no-cors, same-origin, or navigate. The default is cors. In Chrome the default is no-cors before Chrome 47 and same-origin starting with Chrome 47.
  • credentials: The request credentials you want to use for the request: omit, same-origin, or include. The default is omit. In Chrome the default is same-origin before Chrome 47 and include starting with Chrome 47.
  • cache: The cache mode you want to use for the request.
  • redirect: The redirect mode to use: follow, error, or manual. In Chrome the default is follow (before Chrome 47 it defaulted to manual).
  • referrer: A USVString specifying no-referrer, client, or a URL. The default is client.
  • integrity: Contains the subresource integrity value of the request (e.g., sha256-BpfBw7ivV8q2jLiT13fxDYAe2tJllusRSZ273h2nFSE=).

Errors

Type Description
TypeError Since Firefox 43, Request() will throw a TypeError if the URL has credentials, such as http://user:[email protected]

Example

In our Fetch Request example (see Fetch Request live) we create a new Request object using the constructor, then fetch it using a GlobalFetch.fetch call. Since we are fetching an image, we run Body.blob on the response to give it the proper MIME type so it will be handled properly, then create an Object URL of it and display it in an <img> element.

var myImage = document.querySelector('img');

var myRequest = new Request('flowers.jpg');

fetch(myRequest).then(function(response) {
  return response.blob();
}).then(function(response) {
  var objectURL = URL.createObjectURL(response);
  myImage.src = objectURL;
});

In our Fetch Request with init example (see Fetch Request init live) we do the same thing except that we pass in an init object when we invoke fetch():

var myImage = document.querySelector('img');

var myHeaders = new Headers();
myHeaders.append('Content-Type', 'image/jpeg');

var myInit = { method: 'GET',
               headers: myHeaders,
               mode: 'cors',
               cache: 'default' };

var myRequest = new Request('flowers.jpg',myInit);

fetch(myRequest).then(function(response) {
  ... 
});

Note that you could also pass the init object into the fetch call to get the same effect, e.g.:

fetch(myRequest,myInit).then(function(response) {
  ...
});

You can also use an object literal as headers in init.

var myInit = { method: 'GET',
               headers: {
                   'Content-Type': 'image/jpeg'
               },
               mode: 'cors',
               cache: 'default' };

var myRequest = new Request('flowers.jpg', myInit);

You may also pass a Request object to the Request() constructor to create a copy of the Request (This is similar to calling the clone() method.)

var copy = new Request(myRequest);

Note: This last usage is probably only useful in ServiceWorkers.

Specifications

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

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 42
42
41
Some default values for the init parameter changed in Chrome 47. See the Properties section for details.
15 39
39
34
Disabled
Disabled From version 34: this feature is behind the dom.fetch.enabled preference. To change preferences in Firefox, visit about:config.
No 29
29
28
Disabled
Disabled From version 28: this feature is behind the Experimental Web Platform Features preference.
10.1
Consume response body as a ReadableStream 43 ? Yes
Disabled
Yes
Disabled
Disabled This feature is behind the dom.streams.enabled preference and the javascript.options.streams preference. To change preferences in Firefox, visit about:config.
? ? No
Send ReadableStream in request body No ? No ? ? No
navigate mode 49 15 46 No Yes 10.1
referrer init option ? 15 47 No Yes 10.1
cross-origin referrer stripped out and navigate mode converted to same-origin when constructor created from existing Request object. Yes 15 54 No Yes 10.1
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 42
42
41
Some default values for the init parameter changed in Chrome 47. See the Properties section for details.
42
42
41
Some default values for the init parameter changed in Chrome 47. See the Properties section for details.
Yes Yes No 10.3 4.0
4.0
5.0
Some default values for the init parameter changed in Samsung Internet 5.0. See the Properties section for details.
Consume response body as a ReadableStream 43 43 ? Yes
Disabled
Yes
Disabled
Disabled This feature is behind the dom.streams.enabled preference and the javascript.options.streams preference. To change preferences in Firefox, visit about:config.
? 10.3 4.0
Send ReadableStream in request body No No ? No ? No No
navigate mode No 49 15 Yes No 10.3 5.0
referrer init option Yes Yes ? Yes ? 10.3 Yes
cross-origin referrer stripped out and navigate mode converted to same-origin when constructor created from existing Request object. Yes Yes 15 Yes ? 10.3 Yes

See also

© 2005–2018 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/Request/Request