Response.type - Web APIs 编辑

The type read-only property of the Response interface contains the type of the response. It can be one of the following:

• basic: Normal, same origin response, with all headers exposed except “Set-Cookie” and “Set-Cookie2″.
• cors: Response was received from a valid cross-origin request. Certain headers and the body may be accessed.
• error: Network error. No useful information describing the error is available. The Response’s status is 0, headers are empty and immutable. This is the type for a Response obtained from Response.error().
• opaque: Response for “no-cors” request to cross-origin resource. Severely restricted.
• opaqueredirect: The fetch request was made with redirect: "manual". The Response's status is 0, headers are empty, body is null and trailer is empty.

Note: An "error" Response never really gets exposed to script: such a response to a fetch() would reject the promise.

Syntax

var myType = response.type;

Value

A ResponseType string indicating the type of the response.

Example

In our Fetch Response example (see Fetch Response live) we create a new Request object using the Request() constructor, passing it a JPG path. We then fetch this request using fetch(), extract a blob from the response using Body.blob, create an object URL out of it using URL.createObjectURL, and display this in an <img>.

Note that at the top of the fetch() block we log the response type to the console.

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

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

fetch(myRequest).then(function(response) {
  console.log(response.type); // returns basic by default
  response.blob().then(function(myBlob) {
    var objectURL = URL.createObjectURL(myBlob);
    myImage.src = objectURL;
  });
});

Specifications

Browser compatibility

BCD tables only load in the browser

See also

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