Cross-Origin Read Blocking (CORB) Cross-Origin Read Blocking (CORB) ajax ajax

Cross-Origin Read Blocking (CORB)


 dataType:'jsonp',

You are making a JSONP request, but the server is responding with JSON.

The browser is refusing to try to treat the JSON as JSONP because it would be a security risk. (If the browser did try to treat the JSON as JSONP then it would, at best, fail).

See this question for more details on what JSONP is. Note that is a nasty hack to work around the Same Origin Policy that was used before CORS was available. CORS is a much cleaner, safer, and more powerful solution to the problem.


It looks like you are trying to make a cross-origin request and are throwing everything you can think of at it in one massive pile of conflicting instructions.

You need to understand how the Same Origin policy works.

See this question for an in-depth guide.


Now a few notes about your code:

contentType: 'application/json',
  • This is ignored when you use JSONP
  • You are making a GET request. There is no request body to describe the type of.
  • This will make a cross-origin request non-simple, meaning that as well as basic CORS permissions, you also need to deal with a pre-flight.

Remove that.

 dataType:'jsonp',
  • The server is not responding with JSONP.

Remove this. (You could make the server respond with JSONP instead, but CORS is better).

responseType:'application/json',

This is not an option supported by jQuery.ajax. Remove this.

xhrFields: { withCredentials: false },

This is the default. Unless you are setting it to true with ajaxSetup, remove this.

  headers: {    'Access-Control-Allow-Credentials' : true,    'Access-Control-Allow-Origin':'*',    'Access-Control-Allow-Methods':'GET',    'Access-Control-Allow-Headers':'application/json',  },
  • These are response headers. They belong on the response, not the request.
  • This will make a cross-origin request non-simple, meaning that as well as basic CORS permissions, you also need to deal with a pre-flight.


In most cases, the blocked response should not affect the web page's behavior and the CORB error message can be safely ignored. For example, the warning may occur in cases when the body of the blocked response was empty already, or when the response was going to be delivered to a context that can't handle it (e.g., a HTML document such as a 404 error page being delivered to an tag).

https://www.chromium.org/Home/chromium-security/corb-for-developers

I had to clean my browser's cache, I was reading in this link, that, if the request get a empty response, we get this warning error. I was getting some CORS on my request, and so the response of this request got empty, All I had to do was clear the browser's cache, and the CORS got away. I was receiving CORS because the chrome had saved the PORT number on the cache, The server would just accept localhost:3010 and I was doing localhost:3002, because of the cache.


Return response with header 'Access-Control-Allow-Origin:*' Check below code for the Php server response.

<?php header('Access-Control-Allow-Origin: *');header('Content-Type: application/json');echo json_encode($phparray);