PHP: Cross Domain Allow Origin with Jquery AJAX

ajax.js

 $.ajax({
        url: '/ajax/url.php',
        type:'POST',
        data: data,
        crossDomain: true, //essentials
        xhrFields:{withCredentials:true}, //essentials
        success: function(data) {
            console.log(data);
        }
    });

server.php

<?php

			// Allow from any origin
		    if (isset($_SERVER['HTTP_ORIGIN'])) {
		        header("Access-Control-Allow-Origin: {$_SERVER['HTTP_ORIGIN']}");
		        header('Access-Control-Allow-Credentials: true');
		        //header('Access-Control-Max-Age: 86400');    // cache for 1 day
		    }

		    // Access-Control headers are received during OPTIONS requests
		    if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {

		        if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_METHOD']))
		            header("Access-Control-Allow-Methods: GET, POST, OPTIONS");         

		        if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']))
		            header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");

		        exit(0);
		    }
		    
		    echo "CORS";