Ajax Jquery CORS无法正常工作

Hi everyone i'am fighting and searching solutions about this from 3 days. I have a problem getting data from sharethis.com RESTapi. I am working with jQuery and Laravel 5.2. I want to get values from this json: http://rest.sharethis.com/v1/count/urlinfo?url=http://www.sharethis.com but i'am very frustated trying a lot of methods and functions. My actual code is this:

function setHeader(xhr) {
xhr.setRequestHeader('Access-Control-Allow-Origin', '*');
xhr.setRequestHeader('Access-Control-Allow-Headers', 'Content-Type');
xhr.setRequestHeader("Access-Control-Allow-Methods", "GET,POST,PUT,DELETE,OPTIONS");
}
$.ajax({
url: 'http://rest.sharethis.com/v1/count/urlinfo?url=http://www.sharethis.com',
type: 'GET',
beforeSend: setHeader,
contentType: 'application/json; charset=utf-8',
success: function() { alert("Success"); },
error: function() { alert('Failed!'); }
});

This request always return "Failed!". I understand a little what CORS means but on practice i can't make it work. Any ideas? Thanks..

Maybe you actually don't understand CORS :)

These headers have to be present in the response, not in the request.

The server has to provide them.

The server has to agree.

The URL you provided doesn't have CORS headers so you can't fetch it via AJAX unless you modify the backend.

Run this code with XMLHttpRequest to get data

 var url = "http://rest.sharethis.com/v1/count/urlinfo?url=http://www.sharethis.com";

 var xhr = createCORSRequest('GET', url);

 xhr.setRequestHeader(

'X-Custom-Header', 'value');

xhr.withCredentials = true;

xhr.onload = function () {

            if (this.status === 200) {

                console.log(xhr);
            }

};

xhr.send();

And there is the function to check if the url support CORS

function createCORSRequest(method, url) 
{

var xhr = new XMLHttpRequest();

 if ("withCredentials" in xhr) {
   // XHR for Chrome/Firefox/Opera/Safari.
   xhr.open(method, url, true);

   console.log("for chrome/fir");
 } else if (typeof XDomainRequest != "undefined") {
   // XDomainRequest for IE.
   xhr = new XDomainRequest();
   xhr.open(method, url);

   console.log("ie");
 } else {
   // CORS not supported.
   xhr = null;
   console.log("not supported");
 }
 return xhr;
}   

hope it helps, regards