Anil Singh | Code-sample.com

Fetch APIs (and XMLHttpRequest) follow the same-origin policy. The browsers restrict cross-origin HTTP requests from within scripts. A cross-origin request occurs when request a resource from one domain to other domain (from domain1.com to domain2.com). As an Example , // From http://domain1.com/ fetch( 'http://domain1/data.json' )    .then( function (response) {      // Do something with response }); The browser only returns the response if the server returns an Access-Control-Allow-Origin header specifying that the origin has permission to request the resource. Cross-Origin Warning message : - Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://domain1/data.json (Reason: CORS request did not succeed). In the Fetch APIs , we can use no-cors mode to request opaque resources. The cors by default . As an Example , fetch(url, { method: 'HEAD' , mode: 'no-cors' })  ...