//at server side
header("Access-Control-Allow-Origin: https://example.com");
header("Access-Control-Allow-Methods: GET, POST");
header("Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept")

//at client side JS
$.ajax({
        url: source.API_HOST_ADDR+"api/lms/state",
        method:"POST",
        data:{'country_id':1,'apikey':source.API_KEY},
        dataType: "json",
        crossDomain: true,
        success: function(data){    
          console.log(data);
        }
   });## Heading ##

//error: No 'Access-Control-Allow-Origin' header is present on the requested resource